I also have the MSUV and am very satisfied with it but, in my opinion you might be asking it to do more than it was designed to do. That's not to say you couldn't modify it to accept homemade stop blocks but the end results could be disappointing.
By design, the height adjustment mechanism for the rollers/stop block is set by tightening the star bolt handle. Because the tightening process could cause the channel iron to move ever so slightly, setup for precise cuts would be difficult.
IMO anyway, the MSUV is more of a jobsite accessory and wasn't designed to compete with the more accurate stationary miter saw benches.
111,111,111 = 12,345,678,987, 654,321