I agree the main purpose of a WDH is to move weight to the front axle to restore steering control and lessen the load on the rear axle. But since every manufacturer makes a point of their sway control is better than the other guys sway control it has been integrated into any WDH choice and discussion. Even if it is a basic WDH with a add on friction bar. I would think the size of the sail (heightxlength) has to have some effect on sway For example maybe a 20 ft TT may maybe only need a 2 pt friction control like a Fastway E2, a 25 ft TT maybe a 4 pt friction control like a Equalizer or a 30 ft TT a dual cam sway control. Every one of those brands probably had bars for the various length and weight trailer but is 2 pt friction adequate for 30 ft or is dual cam overkill at 20 ft.