[Cruiser]

If your getting .02" movement when cinching the side snubs then you are not running the gibs tight enough. If you have steel balls or use the end of the bolt or set screw in the side snubs then you are also deforming your gibs. There may be plastic or nylon plugs in the snubs, then you won't deform the gib but you will destroy the plugs if overtightened.
In the (any) manual machine there is going to be slop in the screw and nut assy as well the drive end at crank. It is very difficult if not impossible to get rid of this slop.
I have a cnc old 10" model and took out the side snubs for all the gibs. Won't use them, period ! If you have the newer machine with the ground slides and gibs then you should be able to adj the gibs to very near zero play easily and experience no grabbing.
I don't know what your experience level is with machinery but I'd suspect that your a virtual rookie. The key to running these machines is knowing how to properly setup and adjust it from one end to the other.
If your using an oil with a low shear then you will have a much higher resistance to movements than if you used a quality machine oil which has a super strong film or surface tension, which is quite sticky and will not get squeezed out of the run area and allow easier moves.
Six months is not a reasonable time frame for allowing the machine to be run in either, As the slide ways all mate together and show signs of wear It will be able to be tightened up some more and yet move easier, Assuming of course proper oil is used !
A trick to getting slippery slides and gibs is to take some Moly eng assy lube, which has a very high content of molybdenum disulphide, and rub it against all the slides till you can see the moly turning the iron dark. You don't want to leave the grease behind, you want to permeate the surface with the moly, then oil the slide ways and run the machine to the other extent of travel and do that part of machine. you can apply it to any iron to iron surface and it will decrease the friction and allow tighter running. I washed my iron with a strong solvent before rubbing in on my machine and it did make a huge difference, just don't leave the grease behind to attract and hold chips and fines.