ClayMango, the trunks will get much thicker after one year in the ground, so don't worry.. if you have the skills, then there's nothing to worry about.. haha, I'm not calling you out
.. I rather buy a 3 gallon pot and learn from the "journey", then buy a 50 gallon pot and have it fruit right away.. anyone can buy a 50 gallon pot and get fruit but it's no fun..
I put the plants under a "strength training" workout to get bigger trunks.. at least 20 pushups and sit-ups a day for them.. it should be bigger as well by the end of one year's time (June 2015).. give me another year, and this trunk will be wider than your hand..
For example,
Sarnejta (I keep spelling it wrong, but you know what I mean) Custard Apple - bought/planted in June 2014
Last month - February 2015 (less than one year in the ground)