We are embarking on an off road only moose hunting trip here in Alaska in our 406 that will involve hard ground, soft ground and lots of mud. We have michelin XM37 tires in 12.5 width tubeless. What does anyone think is the lowest air pressure I can run without much chance of the tire debeading. We are on stock 11x20 drum brake wheels. thanks for any advice we will be about 50 miles each way off road with some big climbs and river crossings. We will be trailering the mog to the start and finish.