just found the quote from Baldwin and here it is....
RB: I wasn't concerned so much about actual measurements, but as I made progress, I kept measuring my arms until they reached the 19-inch mark. After that, I worked on shape and used the mirror to chart my progress. My waist looked too small at 29 inches, so I used weighted exercises until the muscle expanded to at least 30. The same goes for my thighs. I worked them until they were a muscular 26. My chest was 48, I believe, and calves around 17.
fyi, his arms were not 19 inches, AJ measured them at 17 and 1/4 or so, still some out-fucking-standing arms anyways