I am now proficient at boring! Both to size and to depth, without a DRO. There are 6 bearings to counter bore for and a hole to prep for tapping M12x1.5.
The general sequence for each hole was to align the workpiece to the collet/spindle using an 8mm HSS ground tool rod. The table height was fixed after the first alignment process. Once the work could move on the rod easily, I switched out to the boring head. I found a 0.7mm depth of cut was my limit for stressing the head and its small 6mm bar. After lots of setting changes to get to the correct diameter, it was on to the next hole.
Last step I cut the adjustment slots for the belt tensioning rollers. Not having metric mills I used a 0.25 slotting drill followed by a 0.3125 end mill to cut out the slot per the drawing. I will adjust the idler shafts to suit the changed dimensions.