If i had a friend with a ShockWiz I’d give it a shot out of curiosity, but I don’t think renting one is worth it for most people. Get your sag right, then do some bracketing with rebound and compression adjustments if you have them. Ride, see how things feel and what you’d like to change, then figure out what you need to do to change that. It’s a learning process that’s fun, and not very difficult once you decide to pay attention to it.