All the stability of the fifth wheel is on the outside part of the leg.
You should let the outside leg down to at least the halfway point or more before you pull the pin and let the inner leg drop. This also gives you plenty of room for adjustment up or down as needed to level out the trailer. You should also notice a whole lot less rocking. The motors do go slow but I think you will appreciate the rewards of your patience.
It's not particularly important how mpg is to me. It's how good the truck does pulling up and down the mountains. I bought it for power and ease of towing. It does a great job and the mpg is around 9-10. I have 128,000 trouble free miles.
I've towed a few travel trailers that I didn't get over 8 mpg. Lot depends on the wind deflection on the rv you're pulling.
I've used 4 oz in main tank and rest of bottle in 75 gallon auxillary tank since new. I now have 129,000 trouble free miles and exhaust is clean. I have never noticed any smoke coming from exhaust; never felt any power loss. The truck runs great.
When they wired my 2008 Vue V6 I watched them put another light bulb in both rear tail lights. Directional, turn signals, brake lights and regular tail lights all worked. Headlights did not come on. My buddy has the same 2008 Vue V6 bought same day as I did and they wired his the same.