The burlap will not help to speed up fruiting time (the aerial roots of dragon fruit actually adsorb almost nothing in way of nutrients from what they are growing against, they are not true epihpytes ) but the burlap will definitely be better for grip. I really recommend a fish based liquid fertilizer if you can get any, one with seaweed is perfect. I use powerfeed.

There are two distinct seed types among mango cultivars. Mangos originating on the northern plains of India, in Florida, Israel and South Africa generally have seeds with a single embryo and are called monoembryonic.  The single embryo is the result of cross-pollination, a sexual process, and combines the traits of the male and female parents. Seedlings of monoembryonic mangos will differ from the parent tree. Mangos originating in Southeast Asia generally have seeds with multiple embryos, and are called polyembryonic.  One embryo is of sexual origin, while the other embryos come from the maternal tissue and are identical to the mother tree.  Polyembryonic cultivars have traditionally been grown from seed in many countries.
http://www.fairchildgarden.org/livingcollections/tropicalfruitprogram/jackfruit/growing-a-mango-tree/mango-propagation/

According to the abc gardening website:
"Trees are generally sold as grafted saplings, although some cultivars, such as Nam Doc Mai and Kensington Pride, can be grown from seed sown after removing the flesh. Seeds are polyembryonic, meaning one seed can produce two to four seedlings. Pinch out the strongest seedlings and retain the smallest. This will produce the best fruit."

Would someone also care to comment on this piece of imformation on Burkes backyard site:
"It is worth growing mangoes from seed as they produce up to eight shoots from each seed, only one of which is different from the parent tree. Remove this one – usually the centrally-located, most vigorous shoot – and all of the other shoots sent up are identical in fruit type to the parent mango tree. "
http://www.daleysfruit.com.au/forum/need-some-expertise-on-frowing-mangoes-from/

Monoembryonic mango varieties, like the varieties recommended for Hawaii, have single embryos of hybrid origin and do not produce true from seed. They are propagated by grafting onto seedling rootstocks. Polyembryonic mango varieties, like the so-called common or Hawaiian mango varieties, produce two or more plants of nucellar (maternal) origin from each seed. These plants are predominantly true to type, and may be grown from seed without the necessity of grafting.
http://www.extento.hawaii.edu/kbase/crop/crops/i_mango.htm

The Philippine race tolerates excess moisture, has pale green or red new growth and resists mildew. Its polyembryonic fruit is pale green and elongated kidney-shaped. ... Polyembryonic types may not require pollination at all. Branches may be ringed to induce flowering, but the results are mixed. ... The seed may either have a single embryo, producing one seedling, or polyembryonic, producing several seedlings that are identical but not always true to the parent type. It is impossible to distinguish true-to-type from zygotic seedlings from the same fruit. Some seedlings produce numerous tiny, parthenocarpic fruits which fail to develop and abort. Mango trees tend to be alternate bearing. ... Multiple polyembryonic seedlings should be carefully separated as soon as they have sprouted so not to loose the cotyledons. ...
Thomson (syn. Thomson Large Seedling)
    Origin Vista, Paul Thomson, 1966. Manila seedling, polyembryonic.
Winters (syn, M20222, Southland)
    Origin Miami, USDA, 1959. Seedling of Ono, Philippine type, polyembryonic.

Polyembryonic Varieties

    The phenomenon of polyembryony, characterized by the formation of more than one embryo in the seed, is known to occur in a number of mango varieties growing under different conditions of climate and soil.
    The seedlings arising from the adventive embryos of nucellar origin are highly uniform.
    These can therefore be used as such for the vegetative multiplication of a polyembryonic variety.
    If found suitable, they can also be utilized as standard rootstocks for some of the monoembryonic varieties.
    In India almost all the commercial varieties are monoembryonic, A few that are polyembryonic are comparatively of little economic value and these are mostly confined to the west coast (Kerala) of southern India.
    Some of these are 'Bappakai, 'Bellary, Chandrakaran, 'Goa', 'Goa Kasargod', 'Kurukkan', 'Mylepaliumt, 'Olour', 'Nileswar Dwarf' and 'Salem'. Some of the important polyembryonic varieties grown in the Philippines are 'Cambodiana', 'Carabao', 'Corazont, 'Paho', 'Pahutan', 'Pico', 'Senora' and 'Strawberry'.
    The exact criterion for distinguishing a nucellar seedling from a gametic seedling in polyembryonic varieties of mango is not yet well established.
    In polyembryonic seed-stone the zygote usually gets degenerated and the seedlings emerge from nucellar embryos alone.
    Thus there are chances of the sexual embryo being crowded out by asexual ones in the early stages of embryo development.
    In that case the seedlings emerging will be all nucellar.
    In 'Pico' both the types of embryo develop approximately at the same time and at the same speed.
    But in 'Olour', 'Carabao' and 'Cambodiana' the egg degenerates and all the embryos in a mature seed are adventive.
    Uniformity in the colour of emerging leaves of the seedlings may, however, be a fair indication of their nucellar origin.
    It has been observed that some of the monoembryonic varieties may revert to polyembryony when grown under different sets of soil and climatic conditions.
    Some of the Indian varieties which were mostly monoembryonic produced more than one seedling in the Philippines.
    Similar position was observed with some Indian varieties when grown under Puerto Rico conditions.
    This may be due to natural crossing of the monoembryonic with the polyembryonic varieties commonly grown in these regions.
    The hybrids of polyembryonic and monoembryonic types are polyembryonic under Florida (USA) conditions.
    However, further breeding studies are needed to ascertain the nature of inheritance of polyembryony in mango.
    Sometimes, seedlings with multiple shoots formed from lateral branches arising in the axil of the cotyledonary leaves are mistaken for polyembryonic types.
    However, these can easily be distinguished as monoembryonic or polyembryonic on the basis of the number of tap roots.
    Single tap root will be a fair indication that it is monoembryonic, whereas more than one tap root with equal number of shoots will mean that the variety is polyembryonic.
http://www.ikisan.com/crop%20specific/eng/links/ap_mangoVarieties.shtml#Polyembryonic%20Varieties