I've never had a problem with sway pulling the boler
No EQ hitch.
Keep at least 10% of total weight
on the ball, make sure you have a little toein on the axle
1/8th to 1/4 inch. and ideally the attitude of the trailer should be nose down a little at speed.
It's been pulled across Canada and back and we take it to California every winter which is where this post came from.
The trip down this winter was terrible, 6 inches snow in places, 3inches slush on I 84 around Boise Id. but no problems towing.