>   - Connect it to terminal 15 on the coil & ground to engine.
>   - Connect it to the positive terminal on the alternator and ground to
>     engine.

When setting timing on all my rear-engine VWs I always use the
generator/alternator positive terminal and put the negative clamp somewhere
on the engine.  Works fine for me and I don't have to drag any batteries
around.  The downside is a weak generator that may not produce enough juice
at low RPM to power your strobe, but the Vanagon's alternator works great.

Chris S.
'85 Westy
www.knology.net/~vw/
http://groups.yahoo.com/group/wolfsburg_campers