FYI, this is the reply I got from Aaton.:
Bonjour,
Yes you can. There is no problem attaching a low mode plate to the
16 handle.
What model of camera is it exactly ? XTR ?, XTR Prod ?
In case of a XTR, I would check that the four screws, holding the
viewfinder to the camera front housing, are screwed into four steel
inserts, instead of being screwed directly on the front housing cast
aluminum. The Prod has the four inserts, no need to check.
Best Regards
Pierre Michoud
Aaton service dept