not versed in atlas turntable is it really a 24 inch model? next what size is you longest steam engine with tender? if its longer than 24 inches then that size turntable is out. as to either the ross or the mill house studios that csx al makes that will be a personal choice one is wood and if in a humid climate may have warping issues between it and the layout table top. if you use the all aluminum one csx al sells it actually can be re-adjusted as needed as it really is suspended on 8 bolts not actually tight to the layouts platform.
all 3 other than cutting of the hole in table top for the ross and csx als mill house studios are pretty much plug n play as even the atlas one you need power for the track and power to move the turntable will assume atlas like ross and mill house studios turntables all the wiring for track and turntable motor wiring is pre-done for you just a matter of connecting a power source to each one.
personally I had a bowser turntable and when humidity changed so did the track height from layout table to turntable ironically since installing the mill house studio turntable I have not had to re-adjust it. good luck on whatever you decide to do
