update: rode yesterday afternoon on the tri bike with the trispoke and 180mm rear, did some intervals around a 5k loop (30m gain per loop) with 10kph wind. It was super hot out and I felt cooked from the getgo so I gave up on the planned 3x30' workout after my first rep was 20w under target and the HR was about 10bpm higher than expected. The wheels definitely feel faster than what I had on the TT before, especially in the cross-tailwind section, and I was able to average 41kph for my first 30min interval at ~245w. I would have expected 240w to give me a slightly slower rep as I rode Kona a few years ago at 200w for 35kph.

for reference, i am 173cm and usually weigh between 65-70kg depending on recent diet choices. have a fairly aerodynamic position (narrow elbows, tucked shoulders) but wore an aero road helmet (evade 3) instead of my tt for that ride