I've never been able to level my other 34' class A MH w/o front tires off the ground for months at a time. Sometimes as much as 6" on top of stacked 2x8's...I do whatever it takes. I've had no troubles with frame twisting, buckling, shearing. I've never raised the rear off the tires...the RV has a "rake" like a funny car. Always had to bring the front way up. I keep 100lbs in the air bags inside the coil springs.
2014 XLR 415AMP, 2011 F350 Lariat 6.7 DRW, three bikes, NRA Benefactors.2013=180, 2014=184, 2015=216, 2016=220 jus' completed 7300 mile trek.