peripheral comment
Yes, IR is a good measuring stick for pilot skill in that type of aircraft, in poor wx. I disagree, however, that the PPL vs CPL is as good a tool for measuring pilot skill. Generally, perhaps, but I know a lot of very experienced and well disciplined PPL's with whom I would much rather fly in tough conditions, than many less experienced CPL's I have known. Yes, the CPL has demonstrated a greater skill set upon examination (how to fly), but may not have yet accumulated that wealth of experience to instinctively know when and where to fly...
I flew yesterday in the company of a highly experienced, very well disciplined PPL, in his more than 1M$ privately owned aircraft, and I very much doubt that many newer CPL's could teach me what he did.
If we must judge people at all, let's do it based upon the demonstrated skill and judgement they exhibit, not the letters after their name...
Pilot DAR