Jack,
I peeked into the B+W filter handbook and there it says that the 010 type is just a UV filter which does not take away any light :-)
I had one of these as F-Pro and it was the best filter I have used (glass and mechanical quality).
However, I have found that some things are easier to control with some step rings and some hoods and some caps. Don't know if this applies to you, but I've ended up in having a pile of filters I seldom use and a pile of the other things mentioned and I am always short of these.
You don't need the super slim version of a filter if you have a step ring to put the next size or two steps-up size on. Dito with the hoods and caps.
But hey maybe that's just me cause there is another pile of manual lenses :-)
Best, Georg
PS: Download the filter handbook
here (scroll down to the filter part)