Hey David,
Just a side note.
Going through your equation below, I did my measurements on the crank pulley,
 62cm = 620 mm/72 = 6.21111x5=43.055/10=4.30cm
so taking that and marking that distance on the pulley I get A measurement
But while doing this I found the chewed up timing scale stuck into pulley itself
And found that the above equation result was way bigger then the actual timing marks spacing
This morning it occured to me,
2 rotations equals one stroke so does that above equation need to be divided by 2?

So I was able to time it temporarily mounting the demolished timing scale

But I thought Id point out the discrepancy for others future use

B

1) mechanically determine firing-stroke TDC on #1 cylinder, using a

probe into the plug-hole.  For check, the mark on the crank pulley
should be in about the right place per the picture in Bentley.

2) Mark that position in the place where the scale should be.

2a) :-)  Measure or otherwise discover the circumference of the crank
pulley, then calculate the distance (circumference / 72) represented
by five degrees.  Assuming the engine turns to the right, mark the
crank pulley that distance to the left of the TDC mark.  Now time
using basic timing light, but matching the 5-degree mark to the case mark.

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"