What "tiny gritty feel" ? My experience with Petit Easypoxy is that it is similar
to a spray based paint system in finish ... You can wet sand and buff out minor
blemishes, just like a spray based paint ... I would never spray a plane again
personally as I think you can get as good or better results working in a hangar
or garage with a roll-on system. IF I had access to a good spray booth, then
I would likely spray, BUT I work in less than great places. So spray is too much
of a frustration for me.

Don't use Petit Easypoxy on a fabric plane.