blpetry that oscilloscope scares me...I'm glad it works for you but I feel like I'd need a PhD to use that. My MM has a duty cycle function which I may try next.
Re the Actron: I guess we are waiting for the old fat man to come back and tell us the rest of the procedure we need to follow!
My needle was definitely moving along with the RPM, so I know I'm getting a reading of some kind, but like you and blpetry said, it seems to be reading far too low.
I've also ordered the repair part that the Pelican member Louie85 sells for the male side of the harness connector - mine is totally disintegrated. Not sure if that is part of my problem, but it definitely is broken so needs fixing.