I still haven't come up with a decent name for my Great Northern War square-grid rules, but I have finally posted the latest version to Google Drive.
You can download them here:
GNW Square Grid Rules v1.1
This is the version I used for the Poltava campaign game the other day, as well as the Charles S Grant scenarios. The biggest change is that rolls which aren't used for activating units must be used to rally units instead - in a turn a unit may either activate or rally, but not both.