Well my build was a success! I used the 12vdc fan I pictured earlier, and found a nice little wooden coaster from a hobby shop for 50 cent. Used a forstner bit to make holes for 2 7/8" by 1/2" neodymium magnets driving a 2.5" stir bar (thanks for the ideas here Cat22). These are the magnets and bar Sudbuster used in his great thread "Mega Stir plate". Thanks Sudbuster! The coaster is held to the fan by the immense strength of the magnets, and a small bit of 3m spray adhesive, which indeed is strong bond but removable. I'm also using the 2.5 gallon ankor hockings Montana jar. I was very pleased that the 12volt fan is able to drive the bar through that dense of glass.
For power, I'm using a variable voltage wall wort.
3v and 4.5v do nothing, 6v gets the fan started, 7.5v creates 3-5 inch deep vortex, and 9v makes a ridiculous raging vortex that won't throw the bar. 12v throws it immediately.
Right now it is stirring 1.5 gallon of my WLP 001.
Thank you guys so much for all this help, it was really invaluable! Especially Cat22 and Sudbuster. I will post pics later this evening of the current starter I am running. This was not a cheap stirplate to build compared to others here (factoring all components), but it is the strongest and most compact I have seen ever!
Cheers all, pics coming