964 distributor belt timing

[billjam]

I am just putting a 964 twin distributor back together after fitting new belt and regreasing the bearings. (This is cross-posted here as well as the 964/993 forum as I'm not sure which will get best response.)
I have been following the detailed instructions as per these DIY instructions that I found on a search earlier today, however when you get to the part about fitting the belt and setting the timing between each shaft, they are a bit hard to follow.
What's the simple version on getting the two shafts in the correct relationship?



Also, this little bizzo fell out of the dizzy as I was dismantling it and I can't find a home for it. Got any ideas?