Anyone with an idea on what frequency - how many rotations per minute or second?[/quote]
My Jobo CPE2 Plus rotates at 75 rpm and has bi-directional rotation. I have used the hand roller before the CPE and I just used a constant slide of the hand for 10 pushes one way they reversed the hand movement for 10 pushes the other. I used a 60 second pre-soak and stuck to the development times for inversion processing in a small tank.
I got good results and really strong wrists.