After two paint stores and two big boxes without luck at finding 3M Fineline, I rolled the dice and tried Shurtape Razor Edge Gold. Worked like a charm. I rolled it out with a rubber roller along the edge and backed it up away from the edge with blue tape and had no leaks. It is said to be 60 day tape, but I would not want to push it. Had it on over a week however through many coats and wet sandings.
FWIW, looks like a good alternative.