congrats on your lovely new garter
I've got no experience with northwesterns, but I have a vagrans male, and he is the sweetest critter ever
it's not something I'd recommend with just any vagrans, but I've housed him with other males
since I found out that they're cannibalistic, he's only been housed with one huge marcianus male, but before that he was even for a while in a large community enclosure with five other males of varying sizes - scary to think of it now
he is a rather careful eater, and it appears that he prefers his food dead anyhow
anyway - he's got that endearing habit of sticking his head up like a periscope more than any other of my garters
and while his colours may not be flashy, he is very beautiful, with subtle russets and copper - I'm sure yours looks much better in the flesh also