Hi Kevin,
Went down this route a couple of years ago. I got a REALLY good deal on a Sieg SX4. Wifey told me to do it right & do it once, so I got the DRO, X feed & cabinet too......well she did say!
I went the R8 route as the tooling is readily available, the only issue being you can get 12mm or 7/16 thread in the end, just need two draw bars.
Got it thru Auckland, just had to wait 3 months on the slow boat....but that's ok!
Cheers Kerrin