waaayy back in the '80's when we towed with our 1965 Chevy Van, I used two anti-sway bars, but after almost losing it when two semi's blew by me on each side on a three lane freeway, going downhill, I bought an Equal-I-zer hitch and have been sway free since then.
Those so-called anti-sway bars are stupidly ineffective, they don't start working until AFTER the sway has started so its hit and miss if they will keep you from crashing. While I recommend an Equal-i-zer there are several other hitches out there these days (however, many of those are Equal-i-zer knock offs so get the real thing) that don't need sway bars. Protect your family and get something that works.