To make the jaws accurate to your chuck, chuck a 2" round, and measure the jaws to the back of the carrier (or the nut to the carrier, whatever is higher).
Take that measurement and subtract it from 1. (let's say you measured 0.8", so 0.8-1=-0.2)
Move the model down below the build plate by that amount.

Scale X independently to fit t slot: 
t-slot width / 1 = x scale percentage (the t-slot width is modeled at 1")

Scale Y independently to fit: 
gap between chuck jaws and serrations / 0.25 = y scale percentage (it is modeled at 0.25", it will work if it's smaller, but I like it snug)

Do not scale Z if you want the text to be accurate!