How much promix, outdoor, in thr ground

Hey, new poster long time lurker. I am wanting to do some outdoor this upcoming season and the area i intend to use is fairly secluded.
With that being said what would be the minimal amount of promix i should use to plant them in the ground. I was thinking of going brown dirt style but with the bottom of the bag completely cut out. Could i get away with like 3-4 gallon of promix if the native soil isnt to bad?
I want to put them out towards the end of june so i can have higher number of plants while keeping them shorter/more stealth.

Plan on using leftover GO box nutes on clones till they go into the ground then using heavy harvest.
On a side note, i have leftover advanced big bud(half a litre or so) would it be usefull in addition to heavy harvest?

If it helps. I am in ontario canada, near some great lakes

y would you cut the hole bottom off the bag.... the point of using a bag is to not let the other plants roots from enter and feed off the nutr.. and the bottom of the bag hold water for alittle while so that the promix can soak up the water and absorb the nutrients. other wisr it runs out the bottom and out of the root zone wasting water and nutrients

the big the hole the more soil. the bigger you wan t your plant the earlier you put it out the more soil you need.... in the brown dirt video he said at least 2 cubic feet

The reason i want to cut the bottom of the bag out is so i have the large growth ability of planting in the ground. But for the juvenile growth state it has a premium soil to ensure it has a strong root mass by the time it grows outside the bottom of the bag.

When I plant mine outside, I use 2 five gallon pails of pro-mix per hole. I add a bottle of osmokote slow release fert., a bag of water crystals and a small bag of guano and worm castings to 2 bales of pro-mix. I rarely have to touch my plants from planting to harvest time.