[Lee]

Hi Dan and welcome to the forum. Glad to have another thats interested in these fun snakes! While I can't say much on temperature, as I don't heat my cages (yet) I can give you a few tips with temperment. Having rasied and tamed large wild caught garters since I was six years old, I've found it really isn't all that hard. If you get him and he happens to be a bit nippy, place your hand in the other end of the cage for awhile, let him crawl around on it and get used to it. Most times after doing this and other things that let him know your not going to hurt him he will settle down and let you handle him as garters are generally very docile snakes.
To avoid spooking your garter, don't run up to the cage really fast or make very drastic movements towards the cage mine always hide or jump back at this. Be slow and they won't mind as they know your comming/there!