Yeast recommendation

[1965 wite]

I have been making a corn mash in five gallon batches. I have been using distillers whiskey yeast from still spirits with good success. I am looking for a cheaper substitute yeast that won't compromise my flavor. Maybe something from a grocery store? My recipe is as follows
5 gallons water
5 lbs flaked maize
1 lb malted barley
1 packet alpha amalayze enzyme

I have been thinning it down with about four pounds of white sugar and then adding my yeast around 86 degrees. I have been converting the corn starch to sugar properly but just adding the sugar for a little more kick. Can anybody recommend a good yeast substitute for this recipe and the quantity that needs to be used. Thanks