I honestly don’t know but I’ll give it a shot where it might be possible to add weight. I’ve seen an old article that showed where people have drilled and injected some type of adhesive cement in wood baits but I’ve never tried it.
I’m thinking the area behind the first hook between the first two yellow lines, up to the second yellow line is where the weight needs to be. Before you do anything permanent, maybe hot glue a small split shot to the belly to test buoyancy and how it floats in the water. Then mark it.