fietsbob is right, it's the horizontal top tube measurement you want to size by. ETT on your current ride is 595. If that's a good fit, then the 59 CLX has the exact same ETT and can be made to fit similarly. Head tube on the CLX is about 17 mm shorter so you'll end up with a larger saddle to bar drop unless you run more spacers or increase the stem angle. Some would argue that if you really want the additional stack height, you should select a frame with a more relaxed geometry.