I agree with the others, if the Reese HP Dual Cam is installed/adjusted properly you shouldn't have any problems. As far as the snap-up brackets, follow the Reese HP Dual Cam instructions and you won't have any issues. In some cases do to the amount of vertical chain pull on the snap-up brackets with heavy tongue weights (1,200lbs plus), even Reese recommends bolting the snap-up brackets with standard WDH's with heavy tongue weights. Also, under any conditions (with/without the Dual Cam) do not over tighten the snap-up bracket 1/2-13 lag bolt (only 1/4 to 1/2 turn).., over tightening can cause the snap-up bracket "saddle" to bend over the top of the TT's A-frame.
Yes, remove the old friction sway control plate from the TT's A-frame, the remaining holes will not compromise anything, it's important to follow Reese's set-up/location dimensions when mounting the Dual Cam "Frame Plate". If the Frame Plate is mounted off location this may reduce the amount of adjustably of the Cam Arm Yoke when making you final adjustments.
Also, pay close attention the way the Dual Cam "Hanger Bracket" is assembled to the snap-up bracket chain, and the orientation that it is attached to the "Cam Arm". If it is not assembled/attached correctly the chain will not hang vertical when the snap-up bracket is in the locked position..., the chain will pull out-wards thus increasing the potential for a damage snap-up bracket.
Pics of correct application:
Hope this helps.