I've had the windshield down a long time ago - and none of the horror stories you mentioned happened
There is only 1 bolt on each side that needs to be removed to lower the windshield and from memory they were a LOT easier to take off than the other (painted) bolts that hold the actual hinge on.
It is probably the other bolts you heard about breaking.
The windshield wipers also need to be removed and the 'sport bars' that go from the windshield to the rest of the barwork.
But cant remember anything about access holes in the bottom of the windshield frame while it was down (but wasn't looking for them either).
But I too would like to know if these access holes exist
- there are a couple of rivnuts recently taken up residence rattling around in the bottom of my windshield frame.
With all the aftermarket gear now fitted on and around the windshield frame, it would be a major job to lower it again.
I'd hate to go to all the trouble and discover there are no holes and would not be comfortable cutting holes of my own.