I am heavier than 317 and have put 3000 miles on a Sectuer with no problem, except the wheels. You really want a decent spec wheel built by an expert which may or may not be your LBS. I went through 2 "you'll never break this" LBS wheels before finding Rich Lesnak at Rivendell in California, who built a wheel that went 2800 miles with no problems until the chain got behind the cassette and chewed some spokes up.

DaveW