I totally agree with the truck being too small, but like you, I upgraded to a heavier boat and needed to make a decision.
We towed it home after buying it with a crewcab 2x4 dually, and it was a piece of cake. Backed it down the ramp, no worries. Had to load up people in the bed of the truck to get the boat out of the water.
My half ton 4x4 will pull it out the same ramp all day long in 4 wheel high. But I wouldn't dream of backing down the ramp without the eoh brakes.
So, while its not the safest way to go, its possible if you have electric brakes.
My bad, I thought it was a 4x4 truck, sorry, if it 2 wheel drive, don't even try.