I recently followed the WPOSW recipe with baker's yeast, and I used 1/2 cup for 5 gallons. The more experienced guys on here can use less in their batches and make it work well, but I'm not at that point. I started with Turbos, too, and they were fun to watch - but they always made things with too many off-scents and bad flavors. There's been plenty of discussions on here about how much yeast - some guys dump a lot, some guys use a little and are skilled enough to get them to reproduce enough so that they become a lot.
This is the first time I've used a lot of yeast, and I couldn't have been happier with the results. Baker's yeast is cheap, and I'm doing it this way for the foreseeable future. If you're just starting out and having some trouble, my recommendation is to do the same. There's plenty of other things to work out and perfect - you don't want to be worrying about whether or not you've got any functional yeast in your batch. I'm sure you want to be concentrating on the art of distilling, and enjoying a good product when you're done. Work on the yeast issue later if you're so inclined.
Once, during Prohibition, I was forced to live for days on nothing but food and water. W.C. Fields