Thanks, briguy! That’s really helpful. I know everyone is different, but it’s good to see how others approach such runs.
I tend to keep my HR between the top of Z1 and bottom of Z2 on 20+ mile runs. But, as I mentioned before, with HR drift and rising heat, I usually get right up to AeT for the final five miles just to keep the pace going. (I think I also have a bad habit of pushing through dehydration for the last hour or so, instead of taking a couple minutes to filter more water.)