Hmmm.... sometimes, when it becomes necessary for a decal to cover some awkward angle or protrusion, I will use the tip of a NEW hobby knife to slice a few "breather strips" into the decal... compress it, then after curing, color match a bit of enamel to patch any plastic that's showing.
I haven't a clue about the differences in Revell decals; the only time I ever encountered a problem like that was from using "old" decals. Hope your friend has success in resolving the problem.
![Smile [:)]](/FSM/CS/emoticons/icon_smile.gif)
Take care,
Frank