I would worry about spliting the fuz to put onto boards. The distortion may be difficult to manage. May be better to use splitter board?

For a project like this I often make a very quick splash (thin) mold to lay up a heavy plug in - this gives a much more stable suface to get a good finish on. When doing this I simply fill cutouts with blocks of foam and cover with 2" wide sticky tape. The heavy plug then allows finer finishing of these details.

Making the extra throwaway mold may sound like more work however the joy and time saved working on a more solid plug soon make up for this. I have often gone the 2 mold method when resurecting a favourite crashed balsa model - glue back together - sticky tape and plasticine over the divots - quick mold - heavy plug- mold number two - and turn it into a fiberglass job.

cheers jeff