I never paid too much attention to my paw paws and didn't do anything for them- that they do good in partial shade just inspired me to give them space not so good for other species. My first ones were seedlings from Gurney's- lots of seed not much pulp, but interesting. Then about 20 years ago I planted Overlease and Sunflower. They took a long time- probably 7 years to be big enough to really crop- but I didn't do much to make them more vigorous
They are so much better than my seedlings were, but still not important fruit to me. I am planning on trying to get them going in my nursery though- stick them in in-ground bags for a few years and do little for them. Once they are bearing age they will be worth quite a bit of money around here. I will start with seedlings and graft them over.