Fermentation Temperature

I am planning on brewing EdWort's Bavarian Hefeweizen this weekend. According to his instructions - he said that he recommends fermenting at 68 degrees.

My basement is 70 degrees. I do have a refrigerator with an external temperature controller for it. So I was thinking of firing up the fridge and doing the fermenting in there.

So my question is - to ferment at 68, what should I set the thermostat to? Simple logic tells me - set it at 68. But I'm thinking that with the increased temperatures within the fermentation bucket that the ambiant temperature should be a little lower. Does that sound right? If so - what should I set that thermostat to?

Thanks!

Yeah, I assume 3-5 degrees up from ambient during active fermentation temps. If I were using a temp controlled fridge, and wanted ~68, I'd set it for 65 to start. Pay attention to the thermometer on your fermenter, and if it's getting warmer than you want, turn the fridge down a bit.