To be honest you'll be very lucky to find someone who is willing to take on a full conversion on-site because it's a time-consuming job. Unless the person doing the Job as done the same type of machine before and knows exactly what's required with a full understanding of the wiring etc.
The other problem you have is that many full-time CNC technicians only know Commercial brands they are trained on or will work on machines that have full wiring schematics for.
Not many will work on machines like yours because of the unknown and will run a mile if asked to do so because they know it's most likely going to turn into a cluster fuck.! . . . If they do they will want and need to charge big money because it's very time-consuming re-engineering a machine's control and tracing wires etc when there is no schematic to work from.
It can be done, I've done several on-site, but I've got lot of experience of different machines and all those I did on-site I'd previously done same machines and learned in the workshop so wasn't going in blind.!
This is why your struggling to find a Tech.!