A 60-quart Hobart or a spiral mixer should work well. You will only be making about 50# of dough a day to start so your dough size will be based on about 30-pounds of flour. A 50-pound (flour basis) spiral or a 60-quart planetary mixer will handle up to 50-pounds of flour so either mixer will be big enough to provide you with enough dough capacity for future growth. The mixing of the dough is not the critical part, it's all in how you manage the dough, without effective dough management you cannot have a consistently performing dough or a consistent quality finished crust.
Tom Lehmann/The Dough Doctor