Bob, to answer your second question somewhat obliquely, a few general observations:
-- Valve springs per se do not require lubrication.
-- Poppet valves are typically not lubricated in their guides with engine oil, rather by the inherent lubricity of the fuel (and exhaust) mixture.
-- The cam, cam followers and rockers are most definitely lubricated by engine oil, but in the case of the D.III the messy bits are enclosed by the rocker covers.
In short, my guess is the thing probably throws a bit more oil than a modern engine, but nothing like the total loss system of a contemporary rotary.