General rule of thumb as I've heard is that you can increase normal coverage by about 25% with a mover and see benefit (assuming its set up intelligently..
That light for your quoted area would be sweet.. Roughly 460W/m^2.. (For Americans thats about 7'x4' and about 42W/sqft)..
Thing is a light mover is absolutely unnecessary in that area with two 600W lights.. Your table would be less than twice as long as it is wide, so if anything you'd get more coverage moving them along the 4' length, not the typical up and down the table length motion..
A light mover with a single 1000W on that table would be more appropriate, though not nearly as good as two 600W lights..
How much space do you have to work with?? I'd be thinking 1.0mx2.7m (or even longer).. That would give you 445W/m^2, likely equal in value to 500W/m^2 stationary above that table due to the 25% advantage..
For the record, I used to pull about 2kg crops from a nearly identical table to what you suggested with 3 400W lights above.. Very similar to your plan..