i can't really comment on the geometry question.

as far as miles per day, just do what feels comfortable. 30 miles/day doesn't seem unreasonable, but it really depends on fitness and terrain. Last summer I did santa cruz to morro bay and I remember santa cruz to monterey to be pretty flat with the exception of the climb in monterey up to the campground that's in the kirkandall/spring book. note that i might remember it as flat because there are some larger climbs in the big sur area that overshadow anything in the santa cruz-monterey section.

I tour with 2-3 water bottles depending on weather. over 80degrees and my fuel goes in the pannier and gatorade goes in the 3rd cage. The whole ride last year we never had a problem with water availability. especially the part you're talking about. It all depends. There's a part where it's all farm land and not much water available. We rode through that part quickly and didn't need much water/food. A more relaxed pace might land you there at lunchtime. There was a nice fruit stand with fresh strawberries though, yum.

the kirkandall/spring book says that the farmland is boring and should be just sped through. I really liked that part of the ride because there was no traffic and we could all chat and ride 3 across and take photos while riding. great fun.

you don't say how far or how many days you're planning to go for. On my first day we went from santa cruz to pfieffer big sur, approx 90miles. I don't remember there being much in the way of services between carmel and pfieffer big sur.