Lower Gear Inches or HTFU?

I am approaching 46 fast, I find 40x16 pretty comfortable with no knee probs, hating those headwinds though. Have got to the point now where I ignore what other people think, I'm happy with it and thats all that matters.

67" is fine. In fact, most people on here would agree with you completely.
It's not like you're riding 88" around London.