Its getting late, and I'm hungry! But I'll do one more setup!
After removing everything from the mill's table, I put the ram & turret back to normal position & trammed the head one more time (phew !!)
Then I placed one of the weldments on the table with three 1-2-3 blocks under it so the new datum was parallel to the table! Next, I dialed in the long side, so it was also parallel to the table. Then I used an edge-finder to set the X&Y axis of the DRO to zero. So the front side of the weldment and the base were zero.
Then I moved to location, and drilled two through holes .015" smaller than a .3760" reamer. Then I reamed the holes, creating the 4th & 5th datum's.
Tomorrow I will finish the next weldment, as its time for food