The objective was an easy session. Stay in UT2 and UT1 HR bands.
I decided to just stick to r20 and around 180W (on slides) and see what happened with my HR. I hit the top of the UT1 band with about a minute to go in the session.
It was, all in all, very relaxed.
Tomorrow: Shorter session. I have an 8am meeting. Probably a 10K (UT1) or something.