I first started racing in 1966, long before any computerized Fit kits.

The set up I described earlier, along with front of Saddle to tip of stem = arm length + 3 finger widths was the way to measure a frame.

I reached 6'0" at 15 and 160 lbs but as I progressed to 280lbs plus @ 55 and back to 245 last summer, my seat position stayed the same, while my stem got shorter and my bar extension angle, especially on Triathlon bikes was raised, so I did not knee myself in the gut!

I did my 4th Hotter Than Hell 100 this year, 23 years after my first one: my seat position was the same....my triangle wasn't!

It's rarely rocket science, it's usually just math: then again if you can't do the math.......