With a 4 X 4 and those larger wheel on the truck, against the small wheels on the trailer is your problem. You'll gain some, with adjustment on the pin, and hitch, but you won't get there without blocks or different wheels and tire. Not sure I would do that.
I have the same problem but not the same out of level as your's. Had mine across the country several times. 2 inches down on the front of mine get's it level. I chose not to do it and keep the rail clearance. Hasn't been a problem. Tire wear is fine, although my RorRyde suspension makes it work. I have come within 1" of hitting getting out of a gas station once even with the clearance I have.
Larger wheels and tires maybe,... At this point, what is the height you need to lower the front, or raise the axles?