Here is an article that may help you out with foiling your Mig 15. This article is a little more technical than the FSM article, but does include an in-depth section on painting and weathering.
http://kithobbyist.com/largescaleplanes/tips/MikeMcLeod/metalfoil/metalfoil.htm
I'm experimenting with foil myself and have found this particular article very helpful. Painting over foil can be done, but care, pampering and the application of a clearcoat are required.