As a dealer I have watched the pro's do this many times.
A Spray bottle with soapy water.
A nice softish squeegy.
A heat gun.
If the cars used I would "Clay" the area's first then keeping it all wet with the soapy water,position the piece and then use the squeegy and heat gun to make it perfect!
Sounds real easy!!!
I would pay the extra to have someone else do it!
John