Well unless you have at least half an acre of land to devote to a tortoise, and can keep it outdoors most of the time (though all torties should be allowed outside whenever possible), I would rule out the Spur Thigh. Redfoots are by far my favourite species of tortoise to work with. They learn to recognize their keepers and are extremely interactive, and not at all shy. They still require a great deal of space (I wouldn't recommend keeping an adult in anything smaller than 8'x3'). Since you have chams you are familiar with maintaining humidity levels and whatnot. Redfoots and yellowfoots are high humidity tortoises, and they also have a much richer diet than other tortoises do as well.If you can meet these needs than they are a very rewarding pet to have