FinallyME, I have gotten a tan through a shirt but never sunburn.
I have checked a lot of the local thrift shops and could only find shirts with 35% to 40% cotton. A lot of them would have been otherwise excellent though. Both you and Wandering Daisy have said that shirts with a small amount of cotton should dry fairly quickly so I am going to try out one of the 60/40 synthetic/cotton blends. I can get them for about $1 each at the local thrift shop. I don't use the LS shirt for warmth anyway, it is mostly a replacement for sun screen. I have had 11 basal cell carcinomas carved out of my hide so far this life and don't want any more.