Lol.
Not really sure what to tell you about you plans to brew again. Will it work? It sure as hell should. I'd be worried about leaving the magnetic stick in the beaker, spinning for so long. It just seems like friction on the bottom of the beaker could tear up the glass. Or not, I don't have one so I'm not sure if it would.
Aside from that, I would find some way to cover the beaker while it was mixing. I use glass jars that hold a good 100mL with screw on lids, so I can seal them up when I let it sit over night. I'd still say add the BA and cover the beaker prior to its long mixing cycle.
Parafilm is really awesome for covering beakers and such.