I assembled this last night, and Im really happy with it (not yet attached to desk, tho).
It is a win in terms of adjustability (fully, easily, repeatably), and rigidity (quite.)
Over $600 all up. ($140x2 for the sunwayfoto 99 tripod leveling heads, and another $300+ for the keyboard tray/drawer.)
Degrees of Freedom
This will mount onto a keyboard tray/drawer which provides in/out, up/down, and pitch (3).
The leveling bases provide roll, pitch, yaw, 2nd yaw, (4)) x 2, (8)
The mounting plate provides left-right (1)
total 12-dof. (degrees of freedom)
Because I’m occasionally obsessive, Ive also recently taken my old keyboard tray/drawer (which had issues) and turned it into a separate 5-dof trackpad/mouse tray.
More pics of the whole setup once I have the new keyboard setup integrated.