Yep the Reeves would be the smallest. You could always get a male red ear tho, as they are smaller then females...(tho I did get a 3yr old male who was bigger then any adult female I've ever seen, but he really was the 'exception to the rule' and now lives at Willowbank. He really was a ginormous turtle!!! Especially for a boy!) Had been Very well fed.... :roll: Snake necks (Eastern long necks), get quite big too, so definately Reeves or male red eared slider would be the smallest
Growth depends a bit on food and tank size etc, but they probably double in size each yr or so to start with....