and Ive also got the gibbs set to tight.
Just like the nut, there should be a tiny amount of play in the gibs (you can always tweak it once it's up an running, so leave them a little slack). If they're too tight it'll cause you as many problems as too loose.

Does the table slide freely now? There'll be an initial stiction (about 40lbs worth on my drill/mill) but, once moving it should move easily.