No watts… just time/speed/power data from long hill rolldowns and llloottss of velodrome tests on calm days. Not scientifically optimal, but free.
My one wind tunnel visit cost me $1000 to learn one thing - Keep my head DOWN, a lot. An expensive lesson in the obvious. Tunnels are great in theory (and for PR)… but it’d take days and a lot of $ to go through all the equipment variations and conditions/yaws/etc to make something of it.
Air pressure was another one we were looking at on the day for TTs. That was more of understanding why some days were faster/slower than others.