I'm using the SCT SF3 tuner to pull my 5th wheel camper 27” and I’m pulling with a 2005 Ford F350 6.0 L diesel and I have it programed to aggressive/tow/haul.
Should I engage the tow haul on the button at the end of the shifter also?

 

A few test runs in the same area with and without using the TH would give you the best answer. I'd use the TH mode since it helps hold the revs a bit higher thru the shifts.

 

yes use the button as well