I looked up gilmer pullies online and I think running a drive pulley on the Fluidampr for the scavenging stage could be possible with a low profile machined adapter.
Eg a 24 tooth drive pulley to 36 on the pump.
The adapters damper face might have a concentric chamfered “key” to centre it on the inner barrel of the Fluidampr, with the adapter flange being drilled for the three fixing holes on the face of the Fluidampr.
The outer face of the adapter might have a mounting boss aka stubby shaft extension with key way to mount the gilmer drive pulley.
The mount flange of the adapter might be only around 5mm thick, allowing for a low profile setup.
If you get one made, I’ll buy one too