[Keep on truckin]

I was wondering at what size or weight trailer towing one should use the "tow haul" mode? I have several trailers, from a small enclosed motorcycle trailer that weighs no more than 1000 lbs fully loaded, to a jet boat that weights about 1500 lbs, to a car hauler, to a 8000 lbs travel trailer.
I'm thinking the car hauler/travel trailer definitely, but the boat or motorcycle trailer????