Shopmom, not everyone would agree with me, but I find the 32 HAC closer to a 35 than a 30. NOT in exact measurements of course, but in "feel". It just feels and looks heftier and closer to a 35 than it does to my 30's.
So knowing that you prefer smaller bags and you were leaning toward a 30 but liking the shape of the HAC, the 28 might just work for you. I still think you should attempt to find one to try on in person first though (although I've never seen a 28), but the added height might give you enough extra space where it would be comparable to a 30.
Maybe ask jemzenjewels for the exact dimensions and then use HG's suggestion for the cut-out.