Originally Posted by jyasaki
Well, your physics are backwards (you'd need to move the axle forward to get the rig more tail heavy), but aside from that:
Up until you start towing it... Insufficient tongue weight is a recipe for trailer sway.
Yep, you're right, move axel forward. Trailer sway is relative to what's being towed. Been towing a 430 rib with engine living at back transom. Total rib, engine, trailer combo weight 350 Kg for the past 4 years with a compact size car with no issues. My tongue weight does not exceed 15 Kg, that's why can lift my trailer and stay that way with just 2 fingers.
If yo have too much tong weight while driving a compact car will end frying both rear shock absorbers and tires, not asn issue if towing with a Suv, 4 x 4, Hummer.