I dont know why you guys are wasting your time with epoxy to sheet wings. Use Pro-Bond, Urethane glue to do this. It is sooooo much easier then epoxy and penetrates by foaming action triggered by a light aplication of moisture prior to sheeting. No mixing either just a one part glue. This glue penetrates better then any epoxy I have ever used. I dont vacum bag so this method would probably be prefered if you cant bag them.

In two different sets of idenical wings that I have done I have come to the conclusion the sealing can save weight.

On one set I used 50/50 thinned Nitrate dope and sanded lightly after this dried. I have even used cheap hair spray to seal also. Apply just enough Pro-Bond to make a shiny sheen spreading it evenly with a credit card(one thats maxed out). I have seen a savings of an ounce per wing panel by this method. These are 475 sq in per panel. I am convinced that it works and it has not impared the strength or sealing ability of the glue.