OK, I'll try it. Ordered a white LS UA HeatGear shirt. I already wear sun sleeves anyway.

The discussion about perspiring with an underlayer is slightly interesting. The thing that's true is that if you're bare-armed, at least at normal summer humidity in the PNW, and you stop seeing perspiration on your forearms, you have a problem. Time to finish your bottles and find more water and shade. But with arm coverings, you can't see the lack of sweat. Just something to be careful of. I understand that at very low humidity one never sees it anyway.