Well. The results are this: I learned the hard way. Fine through 11, 1:27 at the 1/2, started to fade at 15, and crash and burn at 22. Finished in 3:13 with some walking.
Not too unhappy since my training was limited.
But, so far I am having trouble with stairs and chairs. I expect this to continue for at least 3 more days.
Next time? Might not be a next time. If there is, I'll be ready or I won't go.