Which tunes for my needs?

[wood4heat]

I am planning to order a Gryphon CS sometime soon and am looking for some input as to which tunes to order. First a little background, I am using a 2003 7.3 that's also in for a 4" turbo back exhaust, an intake system, and an upgraded tranny cooler to pull a toy hauler weighing around 7,000lbs empty and 10,000lbs loaded. I'm in the PNW and practically can't get anywhere without crossing a mountain range or two.

I'll start with my question regarding the 65hp tow tune vs the 80hp tow tune. Specifically whats the reasoning behind the 7,500lb weight limit on the 80hp tune? Is it strictly an EGT thing, will the trans not take it or is there another reason?

Also it seems many people report better mileage with the higher hp tunes. would it then stand to reason the 80hp tune would get better mileage than the 65hp?

Last along that same line of thinking could the 100hp performance tune get better mileage than the 80hp daily driver if driven moderately?

I wasn't sure where to put this so feel free to move it if there is a more appropriate forum. Thanks for your input!