Any question answered...

And therefore irrelevant.

Zipp 303 Firecrest is the only sensible choice if you want a 1500g clincher that's not going to be a lot slower than a 2kg aero wheel, but they won't be in the shops yet as they were only launched at the beginning of this month. Also a smidgen over budget, but you can't have everything.

I'm struggling to see what could improve on the Ksyrium ES wheelset that Sumo currently has, for his budget and requirement