All good points made, and appreciate the feedback.
I finally got my hands on the frame, the since the bosses are only 3" from the headtube I'll definitely go with the Shimano adapters with barrel adjusters.
The project will be an interesting one. As far as I can tell, S3 is a tubeset with the same metallurgy of OX. My gut is that this was the last major investment in steels (2009) before the loss of unit volume in the industry to carbon.
The innovation is in the drawing and shaping. For example the downtube is ovalized laterally at the BB but vertically at the HT, which is hard to pull off when you're already drawing down to 0.4mm in the middle (ish). It's also built as a compact-only tubeset (ST 539 (C-T) with HT 560mm). With True Temper's demise, I'm not sure if you can even buy S3 tubesets these days.
The frame is NOS, was built as a Salsa Primero (
https://www.salsacycles.com/bikes/primero), and has Salsa branded dropouts, but somewhere along the line Salsa pulled the plug and the Asian OEM ended up with some inventory. With the OEM's paint *over* the Salsa red paint, it comes in at 1489g, which is pretty remarkable.
You might also not be impressed with the welds, but if I slop some micro slurry around them before I repaint, maybe I can make myself forget what's under there.
