I should point out that even with a varietal branch grafted into the middle of the canopy, that still won’t necessarily ensure proper pollination.
I posted this the other thread.
On my fraken-pawpaw, I have replaced enough of the secondary limbs in the upper and middle canopy that without hand pollination, I still get a decent bit of fruit. (We’re talking about something like 50+ something grafts at this point.) I would still recommend hand pollination if you can do it. It’s really very easy if you have a few grafts on a each tree though. Paintbrush in one hand, dab pollen from the graft and move 1 foot over to non grafted flower, or vice versa. You don’t have to move from tree to tree. Or collect pollen and move between trees. Each tree is self contained in a sense.