Why not make a regular 5 or 6 gallon batch or whatever, but then just take about one gallon out of it as a test batch for your wild yeast, and pitch normal yeast to the other 4-5 gallons. Then you'll have both a regular batch and a little of it wild. You could bottle or keg the two sub-batches separately, or if you want to do a blend at the end of fermentation, you could do that as well. So that is my suggestion: Keep things separated, then figure out what to do with the different portions later. I do this a lot with my ciders as well as my beers.