Less SuperSoil in bigger pots???

So I was wondering if you guys are using less super soil in larger containers than smaller ones?? For example in a 50-100 gal pot would you still use 1/3-1/2 supersoil? I am only moving from 20 gals to 30 gals but I realized I may not have enough SS to fill the bigger pots to the 1/2 mark. Would I be better off using slightly less in each pot or should I just do 2 or 3 plants using plain roots and a liquid fert line up?? Thanks in advance guys!

from what ive been told, each size of planter requires something a bit different, i believe i heard dioxide uses 3,5,7,10 gal ppots all with a bit of a different formula. i could be misteaken, but pretty sure i got that right.