<<..what is needed is a sticky-back film...>>

Agreed. While I haven't tried MonoKote or UltraCote trim sheets on rotor blades, I have used it on plank fuselages and wings.

From that experience, my opinion is that the adhesive-backed sheets MA sells is still superior for blades. Here's why:

The MonoKote trim is quite thick and not very pliable. It doesn't do curves worth a hoot. OTOH, it doesn't "fold on itself" (i.e., wrinkle) as easily as the UltraCote does.

The UltraCote is more pliable, but if you have the slightest misalignment you get a felony wrinkle; and it AIN'T coming out.

The MA stuff is somewhere in between these two. It will wrinkle if badly misaligned, but you have a shot at smoothing it out.

Steve