My drive shaft rpm sensor is a somewhat like yours Greg. My bracket bolts onto the tail housing of my 904. The movement usually doesn't bother my readings. I really like the dana yoke mount and may try to do something like that on my new Daytona
I was reminded that a fourlink, having a longer instant center, will move the front yoke much less than a ladderbar car. So what we are doing ought to work great on a fourlink car.