super soil for transplant from 7 gallon to 20 gallon (outside)

I have established outdoor 7 gallon pots that are 8-10 weeks old. i want to transplant them into 20 gallon pots using the super soil that i have on hand. question is how much super soil should i put in each pot. do i need to layer the soil as if it were a 1 gallon going to a 10 gallon? or can i pretty much fill it up?

I would say 1/3 to half of Super Soil depending on how much nutes your strain likes