Personally I would of left it with a wing or at least the posts but heres how I'd do it in your case, cut 2 small pieces of lexan the same size as you need them to fill the holes.
I would then spray the body and the pieces the colour of choice from the insideof the body, then I would attach another piece of lexan across each of the holes from the inside with any glue type stuff, shu goo anything that will set it hard and tough.
Then simply glue in the painted lexan pieces from the top, you will be left with a small ring around each hole but will work alot better than painting on the outside of the body.
good luck and hope it turns out well.