They seemed tight to me! I guess I just have a big head.
In any case, Dolby does make children-sized glasses as a standard item; maybe they have some of those. The children’s glasses might have the lenses positioned better.
The other tip is to move your head around to track objects if the 3D isn’t working so well; I find that looking through the center of the glasses works fine, but the edges don’t work well at all, so my peripheral vision loses the 3D effect. If you keep your head still and look around with your eyes, the 3D will fail every time you look at something on the edges of the screen, or really, anything outside a circle right in front of you. I find the same thing on Star Tours, but since the screen is smaller and further away, I don’t notice it as often.
The problem, I think, is that the lenses on Dolby 3D glasses are super expensive, so they make them as small as they possibly can to conserve material. As it is they’re like $12/pair wholesale. Or as I mentioned earlier, it may just be that the dichroic filters they use don’t work as well when you’re looking diagonally through them, in which case the size and positioning of the lenses isn’t the problem.
Oh, I just had a bizarre thought; they do make “2D” glasses for some systems, for people that for one reason or another don’t want to see the show in 3D. Those glasses have the same filter (or same polarizer angle) on both sides, so the viewer sees the same image in both eyes. I have no idea if Dolby offers those, but they might, and Disney might keep a few pair around for guests that request them and they could have gotten accidentally mixed into the regular glasses. Or they might have just been a defective pair of glasses.