(not my beliefs, the beliefs established by the projects here and in the HOH section).
Yes, obviously the PCHA was closer to the NHA/NHL. I prefer you don't see this as a "chirp" but as a reductio ad absurdum argument for why you should not simply assume they are equal at all times and the pitfalls that can arise when you do.
You call what you're doing objective; I disagree. By deciding to treat the PCHA, NHA, NHL, and W(C)HL as always equal, you are already making a subjective judgment, and by treating that as a standard for all seasons, you're going to make yourself a slave to that methodology.
Subjective season by season judgments will do a better job. There aren't so many seasons that one couldn't calibrate it fairly well within an hour. Subjectivity isn't a dirty word; the numbers are what they are; they're the objective part; what you do from there is subjective no matter what, so just be subjective and also smart.