ECT guidance on function when towing

I'm thinking of trying a small travel trailer again. I originally had a Jayco 154BH trailer at about
2,700 lbs dry weight but found my 06 Tacoma V-6 to be lacking in towing ability. My current 06 does not have the tow package. I'm thinking of getting a new Tacoma 3.7 OR a new 4Runner with the 4.0 V6 which has the tow package.

Here's my question, if I get another travel trailer at around the same dry weight of 2,700 lbs.
with most likely the 4Runner 4.0 V6, tow package included. How will using the ECT enhance the towing performance of my 4Runner with the 5 Speed transmission?

How long could I have the ECT engaged while towing up a grade?

 

If you found your '06 to be lacking you will have the same experience with the new 4Runner (same engine essentially) and 3rd gen Tacoma with the 3.5l (pretty gutless until you get to 3000+ rpm). Most of what ECT does is just change the transmission shift points and it can be left on 100% of the time.