Thanks. That is sort of what I figured from reading about it but upon playing with trig calculations I wasn't getting numbers that made sense. I guess using google as a calculator isn't ideal. By reach I meant the saddle to bar distance, but the numbers you've given me make more sense.

That is what I get for being a humanities student! I am thinking that I will get a slightly longer stem and leave my seat a bit further back than on the current frame.

One more question: Do setback posts affect this calculation in a static way? What I mean by that is, say I am using the same amount of setback on both frames--the same setback can be added to either calculation and the TT remains 1.5cm shorter?