David B and I were talking about this and wondered why you would even need the fasteners at the top edges. As you know, early cars (mine) have screws while later cars have the DZUZ. But in both our opinions no fasteners are needed. I never attach mine nor does David.
If you don't do the fasteners then the same tub will fit all Panteras. Maybe you'll bring some to Kingston this year?

Keep up the great work!
Mark