I always thought the forward placement of the hack wheel was done for cornering and braking stability... Similar affects to playing with track and trail... Moving the wheel forward increases straight line stability but takes more effort to steer and can lead to dragging it around corners.... On the salt toe and lean I'd think are gonna be bigger players. Toe in/out will add to rolling resistance... Lean in/out will change the resistance as well and well affect stability when hitting little imperfections in the course
We ran about 2 degrees lean in and 0 toe on ours last year... The lean in was to satisfy the weight bias require for the hack