Swim 1.6K. I really worked on kicking hard from the hips and pushing from the abs, and that wore me out.
Also I breathed every stroke and a half, because every other wasn't enough but every was too much. Every 1.5 stroke means that I keep straighter too. I pull harder on the right than the left anyway, and breathing left only means even greater imbalance. It works okay except that my right ear is not used to the underwater-overwater thing: it feels weird. It can't be experiencing anything different than the left ear does, though, so I must only get used to it.