Just read in the new Sky and Telescope about an interesting drift alignment procedure called DARV (Drift Alignment by Robert Vice. Here is the link to his instructions:
Looks simple and accurate!
Robert Pitt, P.E., Ph.D. BCEE, D.WRE
Emeritus Cudworth Professor of Urban Water Systems
Department of Civil, Construction, and Environmental Engineering
The University of Alabama
Rpittal at charter dot net