Been going to Silver Lake Sand Dunes in Michigan for 40 years and driven every kind of buggy imaginable 2-seat, 4-seat, mid-engine, glass body, Jeep, and quads. Just purchased a RZR4 in the spring and have no idea what to use for tire pressure on the dunes. Looking for experienced suggestions. We have the stock Maxxis Bighorn tires. Having a blast with it but want to make it over Test Hill. Thanks!