I wash and dry in the sun with no problem, what I do is right after I am finished rinsing the car down is hit it with detail spray. After I detail spray the entire car I go and grab the electric leaf blower and get rid of most of the water, then I use the drying towel to get the little spots, yes the detail spray drys out and leaves pink streaks, this is not a big deal at all, if I am going to clay I will just be using more detail spray.
The way I get rid of all of the dried out detail spray on the paint is to spray each panel and wipe with the MF towel, no problems at all.