In the days when machines were bought new for use by operators we were NOT very anal about 'mylar'. We used ordinary, household book covering plastic known as 'contact'.
We simply traced by eye, directly onto the PF glass using a marking pen and used that as our template for cutting the contact.
Rip off the backing paper, quick spray with a water bottle with some detergent in it and slap it on the PF. Rub out any bubbles and leave overnight.
They always looked GREAT and doing this stopped the wear.
We used to be paid $10 cash for each machine we did after work over a few beers by our boss at the time and it was dead easy to do one or two machines each afternoon in an hour - maybe hour and a half.
All this talk of 'mylar' covering playfields is mostly fancy pants BS - in the day we just used cheapo contact. Yes, some pinball manufacturers supplied small pieces of REAL mylar to add around kickers etc but we mosly chucked these and opted to cover the whole playfield with contact.
