I doubt you'll find any loads in 3's or 4's commercially like that...in a low recoil.
You should probably talk to one of your buddies that has a 20ga shotshell press...and see if he will let you make up a few boxes on his press ( you buy the components, he'll help you lookup the recipe, and then you do the work on his press )...that way you have all the liability / he's just helping you. ( I don't load for anyone else --- but they might buy into doing that with you / or just buy a single stage 20ga MEC press, if you want).