You can go online, take the open book test for $15 at imaca.org, and then buy all the R12 you can afford. There are several suppliers online and I will be surprised if you cannot get it at your local NAPA store, with certification of course. In Texas they get $29 per can.
As far as 134 working in California, maybe so, but 420 Benz is an Atlanta. Have you ever been to Atlanta in August? Even if you are in a climate in which you can tolerate the loss of cooling capacity, you better be sure you do a proper conversion, or you will be spending a lot more on your a/c than a few cans of R12.
As Steve Brotherton properly puts it, "R12 is the least expensive component in your a/c system." Unless you are selling your car soon and your conscience allows you to put potential problems off on the seller, changing to 134 is false economy IMHO.
The volume of myths and misinformation surrounding R12 never ceases to amaze me.
Have a great day,