Re Q1: I get about an inch out of 5 turns measuring to the front end of the rockers. So measuring before and after any farther forward is going to show a larger change as you're basically pivoting the frame up about the rear wheels/axles.
Here's a demonstration of the effect...look closely at the wheels to see how it rotates:
Re Q2: if you measure top of tire to fender, and get the same in front as in back then the truck is a bit nose down. So if you're level, yes, the front tire-to-flare spacing is larger.