SINARon vs Sironar lenses and “DB” shutters

[pchaplo]

Running across SINARon lenses (caps mine), some with “DB” shutters. A few questions, as follows:

1. Are/were Sinarons made by Rodenstock? Are the Sinar-branded ones superior in any way?
2. Is there a Sinaron lens that is the “same” as a Sironar-S (rather than a Sironar-N)?
3. I have a couple spare Copal shutters and was wondering if I could get a lens in a DB shutter and simply uncrew it and remount it in a Copal shutter?
4. How does the coverage of DB-mounted Sinarons compare to LF-Film-purposed Rodenstocks?