VeeAte

If the balsa is that thin why not over cover it with another sheet of balsa according to what you have left size accordingly i.e. 1/32" if not 1/16" and then taper sand some capping strips back to the TE. If you go that route you could use some slow set CA or White PVA glue either would work although the CA would be quicker beware it does not sand well. None of this will make any difference to the aerofoil shape or significant weight.

Just a suggestion.

MIke