Design, to me, is a collaborative effort between me, the builder, and you the rider. I like to see what you are currently riding and what you like and don’t like about your bike. From there, I rely on 20 years of bike industry experience and Bike Cad Pro software to design you a bike specific to your dimensions. I use materials from Dedaccia, True Temper and Columbus to choose the right tubing to fit your needs and goals.
As for Bike Fit, I feel like there are numerous approaches to achieving the right size bike frame. Every few years, new theories emerge about how to properly fit someone and I can’t say I agree with them all. Some are more scientific and some are more suggestive. Ultimately, we know how our bodies feel on a bike. For me, I used to ride more of a 56cm top tube when I was racing. Now, as I have gotten older and less flexible, I’m more of a 54 cm top tube. Our fitness levels greatly effect our fit on a bike. One website that I found recently http://davesbikeblog.squarespace.com/blog/category/bike-fit is a great resource on bike fit. I agree with most of what Dave has to say. There are also professional bike fitters everywhere these days, however I suggest you look at what you are riding and take measurements. The aspects you don’t like, make those adjustments. Really pay attention to the numbers- what feels good and what doesn’t.
-ground to the top of the handlebar height
-tip of saddle to center of hanblebar
-ground to top of saddle
-center of bb to top of saddle
-top tube length (c-c)
-seat tube length (c-c)