R-V
GT Fan
Yes a child seat mount is likely to damage any thinwall tube, especially when overpulled, i've seen some sad examples.Think we are missing the point a bit.....whilst i agree that a lightweight frame can be well built and strong for its designed use....that's not what the OP is going to do with it!
Last child seat for a top tube i fitted had a pair of "u" clamps holding it onto the top tube. An no point in the design process did anybody making a tange prestige frame consider that! Considering you can nip a frame with a front mech, a pair of u bolts done up tight enough to stop a child seat swivelling round would i guess risk seriously compromising such a thin tube.
And lgf is correct 501 has its uses.....
PG tubes are cheaper and more resistant to that.