It's been some months now and an enormous amount of research...
I've used the web soil survey site to determine available water but thankfully did not stop at that. I dug into the settings to establish the available water at the correct depths -- not just the default 80" deep data the site provides without digging into the options.
I've done cup measurements but than made additional adjustments based on odd overlapping/quirks of zones of my system in a few cases. --This yielded some exciting new custom nozzle creations
I've established and input square footage for each zone.
I've done more research on crop coefficients for my (Kentucky Blue) type of grass and evaluated based on location and the months that my sprinklers will be running. This has included balancing water conservation and what I want my lawn to look like. ---YES- crop coefficient can be a complicated matter for sure (for starters):
The list goes on but here is the kicker. AFTER taking time to fine-tune the settings for MY yard, irrigation setup, and expectations, the payoff is well worth the time I invested!
My lawn is looking better than it every has. My run time is 20-30% less than it was with my previous "dumb" sprinkler system settings required to keep the grass somewhat green in the hottest months (these savings represent the hottest months and my less water conserving custom crop coefficient settings).
All of this is being done now with more efficacy than a team of on-call 24 hr./day gardeners running my sprinklers while I sit back and don't have to give it a second thought regardless of the weather or month. I know that in the event a weather event is missed and the system does or does not run when it "should or should not have" it will compensate for it in the next watering plan. etc.
The critical part:
I was able to get here thanks to combined information from Rachio community members/contributors.
In particular --- THANK YOU SO MUCH to the Rachio engineers/developers/team for making such an extraordinary product AND allowing the end user such freedom (as well as support -software/professional --and a well designed community hub- to make it possible/understandable) to truly exploit the potential of this wonderfully brilliant system!
Just had to say it.