After my first experience of CW the other day I would quite like to avoid WT in the future if possible.

I am planning a trip to the west coast USA next year (May probably) and was hoping for some advice on the best strategy for booking WT+ and upgrading to CW with AVIOS. There seems to be little availability at the moment but is there a day of the week that would be most likely to become available? We are reasonably flexible with dates. Hoping to fly in to San Diego and back from San Fran but again, this is flexible.

Annoyingly the availability of CW flights on the Rewards Flights Map does not necessarily match the availability of reward seats when booking wt+ and upgrading.