I also have both (CA44 & J5) and have my doubts as to how well either would work under stress. As Mike F above states, the cases do not drop straight into the cambers and require "jiggling" to complete the reload.
I have actually dumped all five rounds on the ground being a bit aggressive with the reload.
Speedbeez makes one spectifically for the S&W M69 L Frame. I haven't tried the M69 version but have used their 10 shot M617 speedloaders and they work as advertised. Not sure how well their retention system would work with the M69 version.
44 Magnum Speed Loader | 44 Mag Speed Loader | 5 Shot Speedloader -Speed Beez
FWIW,
Paul