Zands - I haven't done anything rigorous. One bag of mulch per year. Some 8/3/9 a couple times per year, spring and summer plus chelated minors once per year. Mostly I leave them alone. I follow Richard Campbells advice on tipping to get the trees bushier.
I do the same except for the additional minors. Your chelated minors are applied by spraying say some Southern Ag citrus formula or are they applied to the ground? You have neutral ph?
I throw my 8-3-9 on top of the tree trimmers mulch around my mango/fruit trees because I figure some of the minors will be bound into and chelated into the mulch making for better absorption of minors in my high PH soil as the mulch decays and migrates downward.
But when fruit tree is young/first two years/ I try to tuck handfuls of 8-3-9 under the mulch/spread it a bit/ so the 8 3 0 can get to the roots quicker.
What I really need is to get is some of Har's mostly potassium with minors fertilizer for my older fruit trees. Hey come down to Broward with a load! Guanabanas!
