what are some thoughts on chopping the manky 1/4" button heads on tensile strength at QQ?

Why? If someone chooses to clip them then you just might witness Darwin in action! (Which might not be a bad thing considering some of the heinous people that I encountered during my few trips to the graffiti-ridden quarries).

Pull the bolts and put in some nice stainless steel stuff. I always thought it would be nice to be able to lead at the quarries. A lot of people work to replace 1/4 bolts with good hardware. Not sure why this should be any different.

If you are talking about 3? buttonheads, I placed those years ago ( I think it was around 1990). Feel free to replace them with some good steel. I'd try to get Petzl long life as they actually become knda theft proof once installed.
The bolts in question are actually 5/16" and a fair bit harder to pull than 1/4". Good luck.

john