Helmet shopping!

[OakLeaf]

I can slip my finger between the helmet and the side of my head

That sounds like a huge NO to me.

I know it's typical to fudge the fit on bici helmets, a lot more so than with moto helmets, but I have a feeling that's just because people don't take head protection as seriously when the maximum speed is "only" 50-60 mph as when it's 100+.

A helmet should fit snugly and uniformly everywhere it's in contact with your head. A finger's width would be way too much to me. I'm kind of disappointed the shop personnel let you out of there with that helmet. Remember the basic test for helmet fit is, when the straps are properly adjusted and comfortable, can you rock the helmet in any direction? A couple of millimeters' give is needed for comfort, but any more than that is protection you won't have in a crash. When you try to rock the helmet, the skin of your scalp should move slightly with it.

I haven't tried on a Giant helmet, but I've got a very "long oval" head, and what fits me is Specialized. Lazer are still too "round oval" for me. I'm told that Uvex helmets fit similarly to Spec', but there's no place near me that carries those, either.