I have a 24v Minn Kota V2 auto pilot with a foot control. My 16 Alumacraft boat is a bit to pull being it has a console, carpeting , live well and a casting deck. Add another person, the gear, and down riggers + four batteries and a gas can for the big motor. It adds up. One thing the 24v does is give more time on the water. I use a 12v 55 lb Minn Kota Enduro transom mount motor to push. It helps with conserving batt power when constant trolling. It also gives me that little bit extra when the fish want it fast. We have a few electric only reservoirs and 10 HP limit lakes here. The set up suits them all just fine.
Trolling motors are not designed for speed, but for thrust. The V2 70/24 should be plenty enough for your boat.