Swiss Lathe retrofit

I have done a fair share of industrial machine retrofits and there are others here who done plenty, so it is doable and it does work magnificently. But it does take a lot of reading and measuring and testing to do it properly.
Usually i try to use the existing servo drives and motors that in my case are always analogue +-10V controlled, so for controller i always use Mesa as below:
1X of 5i25 or 6i25 or 7i92
1X 7i77 that has 5 axis plus full spindle control with 6 encoder feedbacks, 32 inputs and 16 outputs. It also has a smart serial connection so 1X 7i84 can be wired directly to it adding another 32 inputs and 16 outputs,
But i usually add a 7i74 and as needed 7i70 and 7i71, 48 inputs or 48 outputs each.
Others do use other Mesa cards, some use Pico systems cards, both are of very high quality and both have extremely good support, as both owners of the companies are members of this forum and are very active.