Bit map works but requires some verctorizing (added work) I have a source for vector files that are already ready to go. No issue there. If you want to send me the decals that's fine, but not necessary. All you have to do is use a ruler or tape measure.
So the material I use is medium tack so it will stick to your surface pretty well for what you're doing, the material is designed for this. It also holds up to sandblasting to a certain medium. Easy to apply and pull off.