-MIKE- wrote in news
You could run a tight string line or laser, level, from the highest
point of the foundation wall to a clamped stick at the low end.
You take a pressure treated sill plate and embed it in mortar on the
sloping foundation wall. You just keep tapping down until it's straight
and level. Let the mortar cure and then insert anchors down into the
foundation wall. The anchors could already be there or be installed
prior to setting the sill plate in mortar.

+1