Dutchy:

I covered my P-51 with chrome monocote. It came out fine, but there are definately some problems associated with the process. Your fiberglass coating on the balsa surface will probably not help the situation, as my experience with monocote sticking to fiberglass is less than satisfactory.

My general impression of the chrome monocote was that it did not shrink as easily as the normal base colors, It will shrink, but one of the problems is that using higher temperatures to increase the shrinkage can tarnish, for lack of a better word, the bright chrome finish. So you need to really plan the covering job, and keep the pieces fairly tight when you originally tack them down. As Jaka said, Oracover/Ultracote will shrink better, but it doesn't have the shiny surface that the monocote chrome provides.

I started on the fuselage by covering the wing fillets with small pieces. You could also run longer, narrower pieces the length of the fillet. Then I cut two large pieces that covered each side of the fuse from the tail to the nose. To help with the air bubble problem, I punched pin holes every 1 inch on the fuselage surface. That way the air bubbles shrink and the air goes out from under the surface. I did the top of the nose with two separate pieces, seamed down the middle of the fuselage. Then I painted the top to resemble an anti-glare panel and was able to hide all the seams.

The wing is a real pain, mostly because of the compound curves involved. As has been suggested, covering the wing in four separate pieces is necessary, but even that won't solve the compound curves on the top of the wing surface. This problem was solved through the use of invasion stripes. I covered the bottom of the wing from the center fuselage out to about where the leading edge of the wing changes its angle with a single piece of chrome, and then from where the invasion stripes would end out to the wing tip. Ditto on the top section. Then you can use black/white moncote to do the stipes on both the top and the bottom. (Yeah, I know that most of the real WWII Mustanges didn't have invasion stripes on the top of the wing, but it looks cool. And makes the covering job easier!) Trying to get all the wrinkles out of the chrome at the wing tips was problematic. I finally gave up and covered the tips as best I could, then masked off a 1" wide area around the wing tip, sanded the monocote smooth, then primed and painted the wing tips red. Again, you have to keep the monocote pulled as tight as you can to minimize the amount you need to shrink. I seem to remember giving the wings the pinhole treatment as well.

It's also lots of fun to try to cover the cowl and airscoop with chrome. My cowl came out OK, but the airscoop is just too small and has too many curves. I finally just painted it with chrome paint.

Hope this helps.