Here's a stupid question - I have two AL wheelsets for my bike - one has a moderately deep section rim, 18 (f) & 20 (r) bladed spokes. The other is a typical 32h Mavis Open Pro set up.

I use two cassettes (with a 53/39 crank) - one has a 12-26, the other a 12-27. I know we're talking minor differences here, but would you put the 27t on the aero wheelset to even things out for climbing or go with the 27 on the Open Pros to have a lighter set for hillier rides?