Autos have WAY too many inherent problems for me to grow them...The biggest is being at the mercy of a seed EVERY TIME YOU GROW....Seeds of course pull genetics from BOTH parent plants...They MIGHT be all good genes or all the worse ones, with something In-btwn being acceptable AT BEST....With photo period plants, YOU CAN clone the best of seed groups and then ONLY GROW known Good plants....And of course, an auto cant be cloned....
Someone mentioned nutes....Some autos can be very nute sensitive...Any LST has to be done in limitation and VERY EARLY....pruning during the point when they are starting to flower can hurt yields big time...Being autos YOUR NEVER SURE when they are going to start flowering, so if topping is in your plan, do it early as possible to get the branching you desire.....Its ALSO A FACT that containers too small for an auto can easily FORCE them to start flowering before they normally would....WITH ALL CANNABIS, Use container sizes that accomodate the size plants would like them to finish as....Your medium choice and buckets are a minimal investment, so there is NO REASON for short changing your plants....ANY SHORT CUTS with growing NEVER SAVES MUCH $$, but can really hurt your end results....
Have you ever considered photo period plants????....Prune, top, LST, all you want to fill your space, AND with the height you need to max out your yields....