What does mix and match mean?
Ride the hot one for a few starts, then promote one of the others for a few starts, then the third one. Doing this would keep all three from achieving Super Two status. Since they're stretching Martin back out, I might even think it'd make sense to do this with the #4 and #5 spots for the rest of the season.
For instance, Perez obviously pitched well enough last night to earn himself a couple more starts, but Folty's still having trouble throwing enough quality strikes to get through a lineup the second time around. Wisler struggled a little last time out, but Banuelos appeared to be pretty sharp. If Folty struggles in his next start and Manny looks good again, send Folty back to Gwinnett for a couple starts to work on fastball location and give Banuelos a couple of starts with the big club to show him what he needs to work on more clearly to make the jump for good. When Perez struggles (assuming he does) Martin will have had time to stretch out and Wisler would have had a couple more outings to improve, so you could call one of them up to give Williams a couple starts at Gwinnett to fine-tune things.
Turning those two rotation spots into a "revolving door" would accomplish a couple of things...
1.) It illustrates things MUCH better for these kids - Folty himself mentioned the other night that he was getting away with some of the pitches that got hit when he was in Gwinnett. It also keeps any of them from consistently getting their brains beat in while hopefully helping the pen a bit. You'd love to at least feel like you'll have a shot to get 6 innings out of those rotation spots more often than not.
2.) Not keeping them up for good once they've been promoted limits any service-time concerns. Assuming Folty's not sent back down, he could be pushing the Super Two deadline. Sending him down (even if it's only for a couple starts to refocus) will keep that from becoming a concern. This also allows you to manage everyone's innings much easier. During their Gwinnett starts you only need to see improvement in the areas Roger wants them to tighten up, and you don't need them to pitch as much as in game action - treat their time there as if you were still at Dark Star..."you were locating the fastball much better today" when you take them out after the 4th or 5th inning, "now go down to the pen and get the rest of your work in" to keep them stretched out without those pitches coming under duress.