FOR MONOKOTE;
While experimenting with lay-ups I wondered about using this carbon veil method for film.
I think this will work;
.- Use whatever core you prefer ! - Balsa ribs/spar/sheer web - foam ribs/spar - foam core - honeycombed foam.
.- 1mm comp grade balsa for skins - will suffice for both mono and bipe wings.
.- 0.2oz carbon veil applied with two coats of 1:1 dope on the inside of the skin having pre-sealed the skin with a single coat of dope.
.- 0.3oz carbon veil applied after skinning the core - one seal coat then apply the veil with two coats of dope/west410/thinners 1:1:1
.- Sand moderately with 600gt.

Based on the wing above this would be ready for film at 230g - all hard points,woodwork etc completed. The wing above is stronger and stiffer than my Midrex wings.
The surface would be as hard as 0.6oz glass and epoxy. If 0.2oz was also put on the outside, instead of the 0.3oz, it would be a little softer but still harder than just balsa.
It would NOT be sealed so should film well. The surface has a texture and firmness similar to non gloss card material (like the inside of a greeting card)
Most Monokote colours cover everything however if you had a feeble colour the surface could be covered with a dust coat of a primer.

I have not tried this and do not have time or material right now - maybe someone has ??

If it works wings for a bipe would be finished and ready for equipment at 300g

Brian