I have used gibberellic acid in the past on a wide variety of succulents.
I have generally found that for the most part the results were
undesirable. Etiolated growth was a very common by product of it's use.
However, with some cucurbits there appeared to be better than usual seed
set and seed maturation. I saw little difference one way or the other in
germination rates of several species with seed soaked in a 500ppm solution
for 24 hours.