Spacer Help- or something better?

I brought up something similar in another topic.

Yeah, trying to get this specific size while making sure it is VEX legal is going to make things WAY harder for you than they should be, at least I would think so. My suggestion would be to either use the thin spacers, since there is more widely available, or to use 4 post hexnut retainers, which can produce a very similar result to what you are trying to get in your CAD screenshot. Considering the route your design is going in, I would suggest trying the 4 post hexnut retainers out and see how you like them. Good luck out there!