Consider the cambridgei. It is fast, modest venom, and will prepare you well for old species. Plus, it’s green. Not a color you find a lot in Ts.
If you decide to go this route, use a slab of cork bark on the side of enclosure that will face you. You’ll be able to see it all the time. Again, if you decide to go this route, beware of a cork tube—they create dirt webs around it and hide inside it all day.
I inquired on the cambridgei. It's also 4" so pretty big. Well, the biggest I've ever kept. are they arboreal?