IDK about being able to produce acceptable grain for smaller sizes. As I have mentioned elsewhere, I take scraps from my 120 size coatings and cut them up as sigle size 35mm frames. The grain is certainly noticeable, but not that bad. "Front Flower Bed" is my favorite 35mm example:
This was scanned on my Nikon LS-40 through Vuescan. It's been printed as an 8x10 and the grain is OK. Being non-modern film it is a little hard to print, though, and I don't feel that I've gotten a really good print but that's OT.
It seems logical to me that as we all gain more experience the emulsions will get better. What is important is for all of us trying these things to keep posting / sharing what we learn.