leveling my truck for towing

[kiwi2000]

I am new to RV ing and tried to purchase truck and trailer so that I would have no issues. It turns out that due to the gear selection choice the truck actually has about 1000 lbs less towing capacity when compared to other choices of gear.

My issue is the truck squats when loaded with the 5th quite noticeably. I imagine that would impact on the steering as well. I have been offered 3 options,

1. a rubber block placed in between the axle and box.
2. air shocks with or w/o compressor
3. add a leaf spring

I had air shocks many moons ago in a vehicle and had nothing but issues with them. I do not know if this technology has improved since. The compressor option is nice but adds to the total. I cannot see getting it as an option and also cannot see constantly changing the pressure either.

I do not see how the block would fix my issue and don't think the box sitting on the axle is a good idea anyway.

The leaf seems to be the best idea but I am concerned that ride comfort would suffer when not pulling? How do I know if one leaf is sufficient?

Anyone else have a suggestion?

The tow vehicle is a 2010 f250 diesel supercab with 3 something gears.
The 5th is a 2010 Montana 285RLD.