I used the machined faces that run up the front of the head for alignment and mounting. I believe that these are the first things to be machined on the head casting and are used for alignment of all other operations there after. Fot this reason I thought it seemed sensible to utilise them as they would mean the quill bracket would be spot on to the quill alignment.
I have seen a few designs that mount using the 4 bolts that, when slackened allow the head to rotate left/right but decided agains this route as when tramming the head the quill bracket would have to be slackened.
You can see some pics of mine here
http://mysite.wanadoo-members.co.uk/...Conversion.htm
Hood