Update spam, pics done, stock arrived. Looking like 32-35 depending on brand is the limit on the back of the seat tube rather than the 38s, due to the shorter road-length stays. If it had longer stays it’d be so close to the Arkose as to be not worth it so no suprise. 25s fitted as std. Loads of space for wider guards etc.
Done a couple of 100+ milers on one now, one in the dark on bigger tyres with a 100 lumen light – ie hit a few minor holes on the way. No bother. Love it. tbh with 32+ tyres the difference in comfort between Al and steel is hard to tell / gone and the impression I got was the lower weight (or same overall as a steel roadie with calipers) and a bit more drive stiffness.
Pyrolite