So I checked a few more out and averaged the length to be 6.634 with no preload. With .050" preload, it's 6.684". Not sure if I want to go with more preload or stick with that number.
Nice, thank you for the link! Those would give me approximately .066" preload. However I do see that they say "with guide plates", did you have guide plates on your build? I do not.