clear mask can be problematic, I would use the cheapest stuff that works well at transferring the graphics.
The medium-tack R tapes and Transfer Rite stuff works great on Orafol 3651 with any laminate I've ever used.(mostly Oracal, Kapco, and General Formulations).
If I know a noob will be installing I will also put center point marks on the top and sides witch a china pencil.
Also tell them to squeegee the back side of the graphic before peeling.