Nessism

There is nothing wrong with seamed tubing, contrary to what some people claim. In fact, controlling wall thickness is easier using seamed tubing which is why some companies, such as True Temper, roll all their tubing (including that used in golf club shafts where flex control and consistency between shafts is of paramount importance).

I know with steel tubing the entire tube is heat treated after rolling/welding to make the material homogeneous - erase the weld on the molecular level (or something near this). Not sure what the Ti guys do for 6/4. Litespeed rolls/forms 6/4 and they have a good track record.

Regarding 6/4 in general, most frames built using this stuff are designed to be killer light thus they really push the tube wall thickness down to the minimum. These thin tube walls are more of a failure risk than thicker 3/2.5 tubes in many cases. The thin tubes also tend to flex more which is contrary to what many people think - they think 6/4 frames are stiff as a rule. Bottom line is that the small details matter.