I have no idea what the art looks like so I wouldn't be able to give you the best suggestion for the specific job. I know that I have wet applied flat sections before, works great ...
paper tape is perfect for that since like others have said you can wet the top of the
paper tape and it will release from the graphics much easier. On the bumpers I wouldn't wet apply, and it really comes down to comfort to application for the tape ... i prefer
paper for it since I can apply on all my flats of bumpers then peal off and use my heat gun and felt squeegee for applying into contour curves and recesses. mostly, If I'm designing the job and if it's a custom stripe, I truly make it custom for the customer ... at which point ... really wet applying is the wrong way to go.