You are making this much harder than it has to be. In any state in the USA (including California) it is 100% legal to
buy pure Ethyl Alcohol for any purpose except to make alcoholic beverages.
I posted links to
two very reliable sources that will UPS to your door.
About Stills:
Also in that posting is information about the use of "heads" or "foreshots" from grain mashes in relfux moonshine stills. If you want to make your own Ethyl Alcohol you must use pure sugar and specialized yeasts. Using grain mashes will not work. Supplies to do this at home are
available here and dozens of other places on the web. Issues with grain mash chemistry is in my link posted above.
About Molecular Sieves:
If you want to turn your 150 Everclear or even 45 proof Vodka into 99.5% Ethyl Alcohol. all you need is a
quart mason jar filled with these. Fill the jar with your everclear and put the entire thing in a cold water bath as the process liberates heat. Leave for 12hrs and pour off the pure alcohol. Then recharge the beads in a 275F oven for 12 hrs and reuse indefinitely. I have used this process to obtain the alcohol for many extractions.
What a Chemist would say:
Retired after 30 years in industrial chemistry I thought I would share this: The 3A sieves and sugar turbo yeast fermentation work like a charm, only if you do not value your personal time as worth anything. In the real world (professional vrs kitchen chemistry), buying precursor chemistry from companies that do that for a living is the way it is done. No chemist makes his own reagents. In your case buying USP Culinary Alcohol from one of the listed sources is cheaper in the long run if you calculate in you time and effort.