The double avatar was fine, because there were two instances on that page that were calling for the avatar; If there were more posters there could be two different avatars there.
The only problem I saw was that they were too large on the one page and it was nerfing your layout. The code I gave you above worked when I tested it, what was it doing that wasn’t working for you? If you have Gyazo or some other way to show a screenshot, that would be helpful, since you are still playing with it and it’s changing when we go to look.
My opinion is that the larger avatars looked great in the other areas of your forum, and that you only needed small avatars in that one spot so that they didn’t make your layout look wonky.