@asm I vote for a queen mattress. If one of the two of you is sick, or on out-of-sync schedules , it can be a big win.
Not a bed person - my spouse is more sensitive to these things than I am and I am more than happy with what she chooses. We’ve been going to platform beds rather than frames+bed springs. Doesn’t address your question though. Note that the only reason I know about California King is from your in-laws. Probably the best place to start?
Retired. Was high performance computing researcher and application developer, working most recently with earth system (climate) and fusion energy simulation models.
Now at loose ends when not helping family or traveling. Indulging interests in philosophy and technical areas that did not have time to learn when working.
Also @whimsy at mastodon.online .