Thank you for the reply and great information. I will post a photo of the mill tomorrow so you get a feel for the size of machine. It is not that large but any further advice once you see the photo would be greatly accepted. I will go for a 3-motor set up to keep the cost down to initially get the machine up and running. I will also make sure the breakout board has the correct amount of outputs to make it future proof. Also the fourth axis I am looking at is fitted with a Nema23 setup.
The information you have supplied is really helpful in going forward with this project.
Still not sure if to go with the Nema23 or 34? But I will go for ball leadscrews not sure about the sizes still need to research options
The Home Engineer