i typically think of GA3 for use improving seed germination, at concentrations between 100-1000ppm. too much can inhibit germination tho
it can also applied directly to plant shoots. probably best to do it on nearly mature plants- it can induce stem elongation, but it can also cause a dwarfing effect, idk all those details. I think it is more often used to induce flowering & fruiting, can cause early flowers/fruits, greater fruit yield, may inhibit seed development within these fruits, use to make hybridize closely related species. it can also be used to help increase frost tolerance.
i have lots of notes on auxin, but cant locate the gibberellin notes. theres some crazy cell bio that happens when these hormones (GAs, auxins, cytokinins, etc) interact in different concentrations in different plant tissues. I wish i could just explain it simply, but its honestly a bit over my head.
i generally think "less is more" with most of these plant hormones, so i would make a dilute solution of 1000ppm and spray meristems of pre-flower or budding plants. and i would leave some plants untreated to compare. see how that turns out, then try it at 500ppm.
just a sidenote, BAP sounds like an interesting hormone to play with, supposed to induce branching, ive read it works great with cacti and brugmansia
too much branching will slow overall growth, might not want 15 pups popping off those trichs, but 1-2 new pups would increase growth points