Smaller Footprint
I think that less space could be takenup it the two slides are offset vertically so that they can truely overlap. I also think with this design that if the closed length of the slide should be the same width as the gantry needs to be to optimise dimensions.
I also think that if you use slides with three sections then the travel can be two times the gantry dimension but with two section slides it will be only one times the gantry side length. This prediction is is as above the width matches the closed slide length.
Cheers
Brian
The Sawdust Creator