Bell housing dialed in.

What a laborious job!
The process: Fit flywheel & bell housing, Torque up all the bolts, measure with dial gauge. Disassemble and adjust offset dowel pins, reassemble and re-torque. repeat till offset is less than 0.005" or 0.127mm tolerance.

I started off by checking the bell housing face was the same plane as the flywheel.

After my first attempt last week went ok till I took the bell housing off and refitted it as I wanted to see how much the bolts could effect it once re fitted as I wont be able to double check it once the clutch is on. Glad I did cos it went back on and was way out. This got me for a while as how to make sure it stays set cos you need to remove it to fit the clutch. After a closer look, I found the culprit. Old offset dowels, I remember Ken at EDA mentioning new ones to me now.
Went and got some new ones, about £15 for 7 thou offset. Checked where the high spot is and marked them as the slots are not to be used as a reference. These were a tighter better fit than the old ones, but this meant complete bell housing removal to move the offset as they now need to be punched out rotated then hammered back home.

So set about repeating the process all over again. Removing 2 flywheel bolts enables you to get the dial onto the inner edgeI tried to mark the housing but soon lost track, so made notes on paper.
I tried different methods, the arrow refers to where the high point of the dowel is in relation to the housing, I messed about with zeroing on 12 o'clock or zeroing on the high spot. I took about 6 attempts to get to number 3 when I noticed that I wasn't setting the dowels at exactly the same angles. 4 was looking better, then 5 came up trumps. The measurements are in 0.01mm so 0.12 would have been a safe tolerance, got it down to 0.05mm. I then had to test that it stayed the same when reassembled so I took it apart and back together, rechecked and all was as near enough spot on the same.
I Was well happy. A good day today!

Thankfully for those reading I wont go into working it all out as looking at the paper I have no idea how I did it, lol.
Andy's blog explains it better and shorted than I could ever hope to.