If you are desperate to avoid the loose setting, it's only a matter of constructing a simple jig to align the spacing off the side of the plate of the Domino, some blocks screwed to a batten would work. While searching for other Festool stuff on Ebay I saw 3D printed things designed to attach to a track saw rail intended to do the same thing (found it or something similar, here -
https://www.ebay.co.uk/itm/186326619817). Seems a pricey and pointless gimmick to me really but if it makes it possible for you to use your expensive tool without freaking about vanishingly unlikely failure modes of joints if it not used only on the tight setting, they might be worth it.