I have a rMBP 15" that I have been using with a 24" Apple monitor. I just purchased a Thunderbolt 27" so I can hook up 2 monitors in clam shell mode. I have the Thunderbolt plugged into 1 of the Thunderbolt jacks and the 24" mini dvi plug going into the other Thunderbolt jack. I have everything working fine but I can't configure the resolution on the monitors correctly. The 24" is fine. It is set at Best for Display mode which happens to be: 1920 x 1200 The 27" Display is way to small when it is set at Best for Display (2560 x 1440) but when I switch it to the next scale down which is 2048 x 1152 the monitor appears fuzzy. I would really like to use the suggested scale of 2560 x 1440 but need each application to display a little larger. Anyone have a solution?