Depends on which era 2x3 Speed you have. If wood, I usually make 1/4 inch thick boards with a 1/8 by 1/8 cutout on the edges. Metal, you need to look around for those.

You need to get a graphmatic for your B&W 2.25x3.25 film, black and white only. If you have permanent spring type back, you need stay with B&W or cut your own.
If you have a graflock back, 120 is the way.

tim