In the ati box with all the paper work it says that all their dampers are made to the absolute smallest tolerances. They recommend that you measure your crank and the bore of the balancer. If it is not within the specified tolerance they recommend then you will have to hone the balancer to fit. They are always too tight. I've never had one be loose. Most cases they require honing.
And for the fluid damper.......those things are only good for boat anchors. I wouldn't even recommend one to my worst enemy. A lot of front seal, lpop and crank failures on 6.0's. when I was big into big block gas stuff, Scat crankshafts would not warranty their cranks if you used a fluid damper. That has to say something when one of the largest aftermarket crank manufacturers does that.