Do they sell what you want in Austen TX? or in San Antonio? I could look?
My garmin says 9.13 km (reasonable, my route choices were not great) but only 309m of climb?!?
I have noticed that in steep, forest-covered terrain like the BCMC Trail on Grouse, the climb is not correct. I don't think the satellites can see the watch, especially when you're in steep gullies or narrow stream bottoms. I haven't thought to check the Garmin vs AP reports cause I'm downloading automagically but I will check.
Re HR strap, I've read about other orienteers who don't like wearing it. Maybe a good distraction to get on top of . Alternatively, don't wear it all the time. I do find if I download my track to QuickRoute, it's informative to look at the HR data at various parts of the race, if only to confirm that "yes, I was uncertain in that area and you can see that my pace slowed" or "here's my pace when I'm running well and confident with my RC". Gives me a sense of what I can aim for.