Are classic parts reliable enough for regular use?

GP4s are very tough - a step down from SSC rims (which were the most heavy duty of Mavics rims, used in the Paris-Roubaix and similar races), but still very tough; I wouldn't have any worries regarding the rims strength. I'd stick with the tubs and run it geared.

Rims are tough, but seems a a bit of metal fatigue has set in, as have already broken a spoke. I was looking to build a geared wheelset, but seems the rear width requires a screw on cassette - so have been told there are limited options. More tempted to run this fixed, with some silver Phils & Grey open pros that will match the GP4's