Hitch advice

[4x4Fun]

I’m new to the fifth wheel world. I have a 2015 Ford F-350 XL 4x4 SRW with all available towing and camper packages. I bought it used. It is lifted quite a bit, has a 100 gallon bed tank plumbed to the main, and a toolbox behind that. I just bought a 2009 Keystone Raptor 3602RL as a functioning DIY project. I’m getting the rig delivered to my house since I don’t even have a hitch yet, and there seems to be LOTS of options there! I’m sure the trailer needs to be level when in tow, but how level is level enough? I’m worried my truck is lifted too much. I’ve heard you can flip the axles on the trailer to get some more height at the hitch. Then I’m concerned about clearance on the toolbox when turning. Any advice would be appreciated as I don’t even know what I don’t know. Thanks!