Mart,
I would not like to think of it as
"protecting the interleaving design".
IMHO, the Intermeshing is the best one (so far
) for small agile craft.
IMHO, the Interleaving is the best one (so far) for larger transport craft.
No single solution is likely to be best for all applications.
In regard to this thread's topic,
this web page might be of interest. It considers the rotor-rotor aerodynamics of an Interleaving disk. This page is specifically directed at a very light electric helicopter. The downwash on the pilot is not considered.
Dave