My camera man weighs in at 285 + gear = 300lbs give or take a pound or so, and no problems whatsoever. I have gone to the extreme and run a boom op plus the cameraman which pushes five bills and can still do forty foot dolly shots all day long. I run a 1.5" thick deck and 1.25" pvc pipe. Holds up to that abuse no problems.
I wish I could get any here. My choices are almost-paper-thin electrical PVC, or pvc-clad copper tubing. The copper isn't all the expensive, though, surprisingly.
There has to be "real" 'States-style PVC somewhere, but the store choices in my area suck.
I was mostly just thinking ahead with this weight question. I doubt I could squish the copper, even if I tried.