I have had 1 12" extension out the back of a contractors saw then onto the out-feed table with the slots over sized never worried about metal miter slots I was using the saw's slots to keep the miter gage straight not the out-feed tables slots sorry Bill I think its an unnecessary cost. It's pretty but unnecessary. I now have a cabinet saw & my work bench is behind it & used as the off-feed table & the bench is set a a height just below the miter slots in the saw top.
I'd prefer a table the same height with slots.
"Forget the flat stuff slap something on the spinny thing and lets go, we're burning daylight" Bart Leetch
"If it ain't round you may be a knuckle dragger""Turners drag their nuckles too, they just do it at a higher RPM"Bart