Is there a reason you don't fold the glove inside, then slide the folded bit over the ring, then put the o-ring over both layers of the glove?I have the Santo smart glove system and use Showa (lined) gloves. The trick to making it water-tight is to turn the glove IN on itself so that no liner is exposed to the water. The o-ring goes inside the glove and the material folds inside this then is placed around the ring. The video I’ve linked to shows the process (but using a 3D printed removable ring to help). It’s possible to do it without this ring (just a bit more faffy).
next time I need to swap my dry gloves I’ll make a video of it.