i have a speed and a graflex d both with fp shutters
and i use the fp shutters all the time.
worth their weight in gold !

the only downside to a FP shutter is you have to wind them back up.
i haven't done it in a while, but it is easy to forget the darkslide is out
wind the shutter and expose the film ... then you say: duh !
and don't do it for a long long while.

i've had a crown over the years too, and never used it ...

good luck !
john