Good to see this forum is getting some action again.
I can't help you with Ray's design. Somewhere on here a while back there was a thread about DIY toolchangers. Something interesting that came up was a kit. If I remember right you could get plans or a machined unit. Going from memory the price was reasonable. I don't think it came with software but that was a while ago so maybe someone solved that. If I can find the thread again I'll post a link to the thread.