I've heard mention of polars that are unique in that they are even more restrictive than our standard polars in how they are mounted. Does LL member Carpow sell these? Would I write him directly? I'm very very interested in a polar with such properties. Would anyone know how I can get some?

You may have misunderstood something I-wrote...
Carpow's 45*-polars are less-dark/'contrasy' than SHC's, for example (not necessarily a bad-thing, btw).
But, they do have a 'directionality' that is odd (and found in at leat one commercial/panel application I've read-of.
With most polars, you just revolve-one until it 'lines-up' with other, and one says it is 'working' (in other words...darker when held to light). With Carpow's, it's not-enough to revolve one over other...they both have to be 'facing right way, or...'no dark'. Only one-in-four possible 'stackings' functions.
That's all that make them odd (nice polars, actually).
He's at:
carpow@126.com
...btw...

HapHazard, thanks for good information. I'm curious about this 'directionality', which is why I want to try them.