Cruiser,
Is the binding once per rev of the handle? This is normal when new as the worm and wheel have to break in to each other. Unlike most geartrains worm gears will actually increase in accuracy with a little use. If the binding is in one direction of rotation more than the other this may indicate that the worm is moving in and out and the thrust bearing (buried inside the dials) needs adjustment. This adjustment is very touchy and you'll need to build a couple of spanner wrenches to get it right.

Don't try to adjust for zero slop. Bring it to zero then back it off until you can just get a little movement on the table. If you don't allow this clearance it will soon make it's own.

If you want to disassemble it and it's the type of table I think it is there is a small pull dowel (a dowel pin with screw threads in it) on the side that holds the worm assembly in place. Pull this pin out and the entire assembly sides out of the table. The spanner nut on the bottom that holds the table in has two small screws in it. Loosen these screws before trying to remove the nut.

From my very limited experience with the geckos they seem to work best with a 500 line encoder. This should give you plenty of resolution while not limiting your top speed. Am I correct in assuming that you are going to attach the encoder to the motor?
Bob