Not to be a negative nancy but I'm not convinced you're going to notice the difference. Chances are rare you'll be in the big/small that often or in the small/big that often either.

Just my thoughts, I can't honestly say that I notice a difference with my 50/34 and my 46/36.

Anyway, like I said...not trying to bring negativity to this, just want to make sure it's something you've tried and really thought through.