I'm using the SteadyFast system on the Cougar and it's very effective. We were going to purchase the king pin stabilizer if needed, but so far, SteadyFast is taking care of all the wobble.
Chocking the tandems nice and tight is still important. Whether you use the homemade ones like mine or the X-Chocks or you use wedges under the tires probably isn't critical. What is important is to get it tight and then check it again. If you set up when you first arrive at a campground, your tires are larger in diameter due to heat. When they cool to ambient temperature, they shrink enough that your initial tightening on the chocks is rendered useless. Mine become loose enough to totally remove them without spinning the nut at all. Tire shrinkage when they cool is probably enough reason to skip wedges and go for the clamping chocks.
I also think that fully extending the scissors jack stabilizers defeats their purpose. I prefer to build up under each jack enough that they extend only about 50% to do their job.
__________________
'11 Cougar 326MKS loaded with mods
'12 Ford F250 SuperCab 6.7 PowerStroke Diesel
Amateur Radio: KD2IAT (146.520)
GMRS: WQPG808 (462.675 TPL 141.3)