After 24 hours (time neede for the putty to cure) sand your entire plug.. by hand... shaping the final contour you want..if you want to have a 3D gill, it should be engraved or ethched at this time, I use a dremel tool with a triangular flutted cutter.
Now coat your plug with adhesive from the gill mark to tail ( I use duro spray adhesive) spread you mesh and press into place, once the glue and mesh have set, trim it to fit the countour of your plug.
Now lay the plug on a strip of foil, I fnd that the stickey backed foil used for duct work to be the eaisest and most durable/shapable...
Trace your plug and cut out the shape, this piece will fit the side you just meshed.. clever huh?
Now peel back the backing and lay the foil on the plug.. if you screw it up, you will have to remesh and refoil, I find a rag dampend with turps handy to keep adhesive off my finger, which also keeps it off the foil..
press thge foil into the voids with your thumb, I use the a wooden q-tip(cotton removed) to press the foil into the voids, the wooden"dowel is also used to burnish any wrinkles and to flatten the edges... repeat on the other side..
Some people that foil plugs make the seams meet, I do not, I prefer to sand the edges with 100 grit paper so they blend ito the wood on the belly and on the back, on the flat part of the head, I use a utility knife to remove any flased over foil.. I then prime the bare wood with the bins primer.