I have Ultegra/CXP33 rimmed wheels. When I got them, my LBS owner said -- "I hear they'll beat you up a bit." I had no idea what he was talking about.
Then I learned. They are stiff and unyielding.
I bought a pair of ROL Volant wheels, used but in good shape -- look 'em up, they win awards -- and I couldn't be happier. The other day I put on the Ultegra/CXP33 wheelset thinking I'd use them from now on, i.e., for winter riding and commuting, and keep the lighter/faster Volants for spring and summer. Uh uh. Nope.
So my advice is: Get something other than the Ultegra CXP33's.
PS -- I'm 6 one, 180 lbs, and I ride a titanium 'cross bike as my all-'rounder.