My ERA is an early one, #154, Pats is a late one #732. Many years apart, same slave cylinder, simple, effective, works. I've had this same basic setup, slave and spring on many different kinds of cars over the years. The biggest problem I encountered was where to hook the spring? Sometimes a hose clamp on a header tube, funky, but gets the job done.
I don't know why some guys are having trouble with the spring not being able to return the fork to it's lowest position. Thats a head scratcher....