On my Dearborn 10-10 2 bottom plow, it is made so that you cannot hook up the sway bars when it's on the Ford 8N that it was designed for... and it works just fine without the swaybars also.
I think you need a little room to "wiggle" when your plow is in the ground... I wouldn't hook up the sway bars, or at least not set them tight. You want the plow to be able to move side to side a bit. If it's set right, it will draft correctly and the swaybars will not be needed when it's in the ground.
The only reason you should need swaybars with a plow is to keep it from swinging into the tires when you're turning around. If you're thinking that you'll need them to keep the plow going straight, then you need to get your plow set up correctly... it's not the swaybar's job to make the plow track correctly... that's in the adjustments.