It's good you know your measurements--it helps a lot in the acquire/sell bike arena...or self control arena. My frame size range is 63-66cm (CTT) with a top tube length of anything 57-60cm (CTC) if given/"normalized" to a 73° seat tube angle. I'm selling a lovely Paramount frame that is a 62cm CTT and that simply doesn't allow me to get a good looking bike while also being in the comfort range. Well, unless I don't do classic drop bars. It's about proportion with me and I don't want a gawky looking bike, trying to compensate for a more extreme saddle to brake hoods drop/distance. Interestingly, a 66cm bike will have its top tube hit my inner thighs when rocking the bike out of the saddle when climbing or accelerating. It's actually a little bit limiting. 63-64cm frames have their top tubes obviously a little bit lower, and that's the difference. All the times I think about having or building a custom frame for whatever reason(s), and then I go back to the reality, more and more, that I'm riding the bikes that fit me well already. That's pretty cool!