I am new to the world of Festool Dominoes. I had my eye out for one on CL for a while and finally got a Fat Man at a decent price (never did see any Little Boys come up). With a Seneca adapter and a set of smaller bits, I am good for any size of domino.
My current project is a(nother) platform bed, and there are several places where I am using lines of dominoes, for example joining side- and end-rails to the plywood that the mattress will rest upon. I did some test pieces using the cross-stop and cutting lines of narrow mortises, but never could get them to align. I know there is a way to calibrate the cross-slides, but after about five attempts (cut several mortises, adjust, cut several mortises, adjust, try to get them to line up), I gave up. Perhaps someone has a better way to calibrate the two cross-stops to each other. Of course, I could follow the Festool suggestion to just cut narrow mortises at one end for alignment and then cut the remainder of the mortises at the wider setting. That works, but it offends my sensibilities: I moved up from a biscuit joiner to the Domino for greater precision, and those wide mortises are pretty sloppy.
Instead, I have been scribing domino locations on pieces to be joined and aligning the cursor with the scribe lines to cut narrow mortises. This is slower and more painstaking than using the cross-stop, but it works! As a hobbyist, I am not as concerned with efficiency as others might be, but I was wondering what other folks out there do.