It looks like you have received excellent feedback.
You should be able to get prices on a rebuilt PH9 from Renishaw direct. They are located in Ill.. If you need a # let me know. With your application, I would like you to explore a price on a PH10 also. If the price difference is not staggering, this would be a better fit for your parts.
If Renishaw does not have any, ask them for the name of your local dealer and have them do a search for you.
The price for the head and controller should be around 10k with a rebuilt one. Also ask them if you can trade in your MIH. If it is in good condition, you should be able to get between 2k and 3k for the head.