Doug, I haven't tried them on a Dominator. As you undoubtedly know, there are two conflicting "unintended injury" issues with shoulder belts on a Bensen-type gyro:
1. The belts must be attached to the structure above the pilot's shoulders. If they just loop over the seat back and then down behind, they can compress the pilot's spine during a sudden stop and cause back injury, but...
2. On a Bensen-type gyro (which requires an unsupported "pole" mast), the mast is the logical mounting point to meet Criterion #1 -- but that introduces a serious new problem. In a blade strike, it's not uncommon for the mast to snap off at the seat back. With the shoulder belts attached, the broken upper mast piece will pull violently on the shoulder belts. This could be lethal.
Ideally, the shoulder belts would not be attached to the mast, but to a separate structure extending up from the keel, not attached to the mast. This structure might take the form of a roll bar; not a bad thing at all, but of course it adds weight and complexity.