I've installed several 54/55 windshields and have had problems most of those time.

1. Greg's advice is excellent.
2. If you have an original windshield, you should then have no problem.
3. Repro 54/55 windshields might have bends that are slightly-off and will cause difficulties.
4. Repro 54/55 windshields might be slightly larger that originals (if patterns were made from existing windshields to make the repos (rather than using original patterns) - each incremental pattern might be a tad larger than the original).

This summer, I hope to be installing a NOS 54/55 windshield with the stainless trim and with a Steele seal. I'll post my experience at that time (sorry this is of no use to you at this time).