An idea:
I haven't done this so YMMV.

If you're trying to reconstruct a failed deck core, and the boat can be
turned upside down, then you can cut out the inner skin and the pulpy core
and construct a new core and inner skin working DOWN. If that's not
practical, how about laying the boat over on its side? Wallpaper is not an
impossible PITA.

Working overhead, I've had a lot of trouble in relying on stickyness of
resin.
If you really have to work overhead, I'd try very hard to devise a vacuum
bagging method. The conventional arrangement of laminate|peel
ply|bleeder-breather|bag depends on gravity to keep the resin and air where
they should be, if there's a choice. Invert it and you'll end up with airy
laminate and saturated bleeder-breather. NG! Maybe substitute a thin
transfer medium for the b-b or leave it out and suck from the top side
through perforations? THis could get complicated.

Of course, the practical solution is to cut out the top skin, re-laminate
working down, as the god of gravity intended, and finish with a gritty paint.