For anyone who has worked with Vivian, this may be redundant. But, for others, it might be useful.
I am looking at her tunes, and she sent me this e-mail with some specifics on each. This may give you the information that you are looking for. It looks like she doesn't recommend tunes when towing more than 10k (except for the Transmission Only File), but you mentioned 6-8k. So, you'd probably be fine with a few different options.
Economy - is designed for bumper-to-bumper traffic to reduce turbo lag. You can save between 2-4 mpg. (40rwhp)
Economy Only - We have found that most people get the best fuel mileage from our Looney tune, as long as they are not always on the pedal. This file is designed in the image of the Looney but does not contain performance parameters. You can save 3-6 mpg. With this file you cannot tow at all. (40-50rwhp)
Transmission Only File - We do not recommend towing more than 10,000 with a file, any file or anybody's file. This file is the alternative. With the transmission shifting properly you will feel the truck to be stronger (+/- 20hp).
Tow - is designed for pulling. A normal tow file is about 50hp, when aggressive can range between 65-75. We can also add jake brake to any tow file. This feature works with the exhaust back pressure in your truck and you must have your tow-haul on when pulling weight but don't need to turn tow-haul on if not towing.
Street - is designed for highway driving. It's drivability parameters are intensified for ease in passing and maintaining higher speeds for longer periods of time. (90-120rwhp)
Looney - is designed for daily driving. We've been told it shifts better than stock and as long as you are not always on the pedal, you will save FUEL! It is the highest daily tune that we will send via the net without physically tuning your truck. (130-160rwhp)
Looney Wild - 20-30 hp more than the Looney but we only offer to customers with aftermarket headstuds.
Looney Wild Track - Same horsepower as the Looney Wild but you don't need headstuds to run this file since it is NOT a daily driver file. It is only for racing and competition pulling. Basically what we do is take away a lot of the drivability to give you more power to the ground.