There's pros and cons to the long throw polishers. Do some research to figure out what will work best for you. The G9 would be a big step up from your older polisher.
Better yet, buy a roll of clear mylar from Amazon for $10-15. Tape it to the inside of the glass. Replace as needed. I think the roll I bought was 100 feet long, so basically I'll never need to buy another roll.
This can't be the first time the shipping dock has dealt with something like this. Did you bother asking them for their recommendation? Who locally could handle the job?