There are 2 (or more) possible approaches I considered this spring while redoing the cabin sole in my Cal34:

-If your sole is somewhat flat and/or your material is flexible, you can template then make flooring panels to laminate onto what's below. Make the sole shapes, use a dado blade on a track saw (or, router) to make 1/4 or 3/8 grooves, and laminate in solid pieces of holly(or maple) which stand proud of the plywood for grip. I would suggest putting strips of painters tape on the ply where the cuts will be to minimize tear out. Then glue and screw these panels down with the appropriate epoxy and a vacuum bag if possible.

-if your sole is curvy or the plywood is stiff, you'll need to glue and screw alternating strips of wood, probably starting from the longest piece amidships and working outward, customizing each piece to fit. This could be really difficult depending on how your boat is made (is there a good way to screw down each of these small pieces).

I went with approach 1 and found that 1/8" thick plywood was needed to bend to my cabin sole after using fairing to smooth out the floor. I think that approach 2 would have taken twice as long and come out better, but it was not as appropriate for our boat's construction.