I have a 1959 5Ta that has been changed to EI. The PO carried out this conversion so afraid I can't help with the finite details, but I know he had to blank off the distributor aperture and fit a later timing casing. Other than confirming it can be done, not much help I'm afraid
I have a 1961 T100A with Boyer fitted to the 18D2 distributor. I got it from AO Services, they modified the Boyer, sent it to me along with instructions of where to machine/file if it didnt fit, which it did. Or apparently they can do all necessary distributor work. I can only go by my own experience, but in my case this was a much easier and quicker job than having the Pazon fitted to my 6T distributor by the firm mentioned above.