or anyone who has used 170 degree hinges on face frame full overlay cabinets of any manufacturer - did you have to cut the overlay frame?

These are the only type I know of that will work. Here is a link that might be useful: hinges

We had one of our baths remodeled last year with about the same dimensions, 28 X 46. We have a frameless door, I think it is like you described, works like a "regular" door. Our prior shower head aimed toward the door but it was a 25 year old framed door. We now have a rainshower that although not attached to the ceiling, aims straight down, rather than at an angle. We also have a sweep at the bottom that seems to help a lot. We do get a small amount of water that leaks from both sides but I wipe down the entire shower after I use it every time so it's no big deal to wipe down the small amount that leaks.

Keep in mind that there are two elements to the upcharge: The hardware cost difference and the labor cost difference. Most of the cabinetmakers I have talked with have said that they initially upcharged for the Tandem undermount soft-close slides. However, once they'd used them a few times, they realized they were saving a lot of time on installation because the slides are so forgiving and adjustable - so many cabinetmakers no longer upcharge for those slides. IMO anyone who tries to talk you out of those slides just doesn't want to learn any new tricks. And agreed with the comment above: Plan for those drawer slides now - the retrofit soft close bumpers don't compare at all.