The holder you want is a 545 or 545i.
For portraits you don't need a lot of camera movements, but you want enough bellows to get in close for the lens you are using, and some front rise and fall can be handy. There are lots of good cameras out there. As long as everything is straight, steady, and the bellows is light tight, you'll do fine. Among old wooden flatbed cameras, it's hard to recommend one over another without knowing the condition of the particular cameras you're considering.
If you go to lfphoto.info, there are some good articles on the main page about the general types of cameras that are out there.