The way it looks to me, if the drive was designed to have forced oil
lubrication, you can't just add a reservoir. You'd have to also add an oil
pump, and maybe some other form of cooling.  I'd also have to suspect that
our fearless leader would have used a reservoir system for the RD-1 drives
if there was a significant overall advantage (including weight, complexity,
etc).  

Cheers,
Rusty (got home at 5:00 am after hauling my new Airbike project back from
Arkansas)