The pattern does fade by afternoon when it heats up here -- and it's been known to hit 100 in April now, unfortunately. And of course my mini bed gets full sun almost all day, but it's in the one spot (beside stairs going to my upper back yard, and the bed is hip-height so I can see the blooms more closely) that just screams for minis. But my TET STAR CHILD that I keep under my pergola does keep its coloring on the blooms really well, so I think your idea of putting it in a place where it won't get later afternoon sunlight would be a really good idea.
Several minis and smalls with this type of pattern come from Liz Salter's hybridizing program, and another one that I would recommend is her CIRCLE OF WHIMSY, which is one of the color changers. I have some pictures in our database if you want to check on it -- I think it's amazing, although so far it's not very vigorous. Of course, it would have helped if one of my cats had not decided to camp out in/on that pot, probably for a few days before I discovered her, but she did! So it is in recovery mode right now, and I suspect there will be no blooms this year...
I've also ordered PINWHEEL PRINCESS and can't wait to see it bloom -- sure hope it blooms this year...