Has anyone ever used one of these before? Not sure if it's worth it or if there is an easier way to determine the offset. Thoughts?

Link: AutoWare Technologies, LLC, Makers of SoftWheels

FYI I'm trying to achieve a wide tire just inside the fender (no stretch). Nice and tucked in. FWIW I love Diego's latest setup (CV2's) and may go that route but im not so sure yet.
Anyway im just another confused soul .... lol