I've used and installed all three brands of BB gear drives, Donovan, Milidon and KB. I don't remember which one uses which pieces to set the back lash, they don't all use the same parts and procedures though
On the Milidon they send you a bigger alignment dowel for replacing the stock ones, you remove the stock ones and use a piece of newspaper cut to fit between all three gears and push the gears up tight so the paper will move when you rotate the crankshaft and camshaft and then tighten down the cover and drill the pin holes out to the size of the new pin and install them, works good
That cover has a harden insert press into it that barely fits onto the new dowel also
I don't remember much about the other two
I recently reused the Milidon on a bracket motor I'm building for myself is the only reason I can recall the details on it, I bought the new bigger alignment pins from Milidon last year
I do have the original installation instruction on paper for it also
I wish I knew how to scan and attached it on here, but I don't