The vast majority of ants are good climbers. I find its very very rare to find an ant that is bad at climbing. Plus, I have yet to find a small ant bad at climbing. But, even most bigger sized ants are good at climbing, so size doesn't seem to matter much.
However, very large ants can be easy to keep too even if they are good climbers (I assume bull dog ants can climb good). In Australia, I heard bull dog ants are really easy to keep contained, because they are so large that they can't find through small holes like other ants can. I imagine they can climb, but maybe not actually, I don't know that detail. I just know that (despite being super fast), they are really easy to contain in most lids/barriers compared to super small ants. Someone said some time back over on Antdude's forum that they are super easy ants to contain just because of their size. I don't have any experience with that though as I've never even been to Australia.
As for ants in the US. I find the #1 hardest to keep contained are the west coast Monomorium ergatogyna (and Monomorium minimum are 99% the same, but the east coast variety), they can cross even fluon. As a test, I separated the Monomorium and put Argentine ants in the container, and even the Argentine ants couldn't cross the same exact barrier of fluon (and Argentine ants are super good at escaping), but the Monomorium ergatogyna could without any issue at all. Then I tried Solenopsis invicta (who are quite larger) and they too couldn't climb it. Monomorium ergatogyna are so tiny that any dust particle they can climb on. The #2 hardest would be Solenopsis molesta (despite being a subterranean based species), but they too are super tiny.
So, if you want easy to contain ants, stay away from small/tiny ants as they seem far harder to contain than larger ants, but I suppose that makes sense.
Edited by Vendayn, February 9 2017 - 9:44 AM.