I have it in mind to fasten the first two planks aside on the jig, then flip the centreline over onto a strongback and continue the planking right way up. That way I can visualise the shape better, make a start on cleaning up any glue runs, and even start fitting floors, as one would in a traditionally-built boat. I can also prime as I plank, so that when the sheestrake is fitted, the interior will be ready to fit out.
It will take a little more time initially to turn the boat and shore the moulds to the ceiling, but I reckon the time saved at the end will more than make up for it. And having built all my boats that way, why change simply because the material is plywood rather than larch?
Will it work? I see no reason why not. And I will be using a glue and Gripfast nail technique I trialled successfully on a small plywood dinghy a few years ago. Again, I think it should make the whole process more enjoyable as no one I have ever spoken to has anything nice to say about mixing epoxy.