Hi Robin,
yep, we've been through quite a few methods including phd guiding and alignmaster.
we've found this method to be the most accurate, correct me if I'm wrong John.
its actually quite easy and removes the ambiguity you may have with the phd graph and whether its going up or down cause sometimes, it looks like its stable, and then it changes for a bit and then stabilizes.
with this ccd method, its very straightforward and either a straight line or a V.
as explained here
http://www.observatory.digital-sf.co...nt_CCDv1-1.pdf
It should be possible to move the G11 east and then west with a script.