I'm about to embark on my second frame, a 650b wheeled "path bomber" - a bike primarily designed for the packed gravel paths in my area, but also at home running to the store and riding around the neighborhood with my kids.
My initial thought is to use 9/6/9 road OS tubing with a lugset (one of Dazzas) built for a sloping top tube design. I built my first frame from Columbus SPX, so similar butting, but standard diameter. However, I'm using Ceeway to source parts for this build, and the only tubeset he has that is 9/6/9 road OS is seamed Dedacciai. For a number of reasons, I'm not wild about seamed tubing -- unless todays seamed bicycle tubing is significantly different from the seamed tubing of 20+ years ago.
However, there are lighter gage (8/5/8) heat treated road OS tubesets that would also work, but I just want to make sure that I won't be building a noodle. Is a good heat-treated 8/5/8 road OS tubeset too light for a 240 pounder? I'm a spinner, not a masher, and my competitive days are far behind me.
Any advice would be appreciated.