My pizza crust is very hard and tough and not light and crispy, why?
Your 60 qt mixer is going to mix dough at a much different rate than your 20 qt, even if their rotation speeds are the same. Your hook to bowl clearance shouldn't be an issue unless you're getting an excessive amount of crusty dough on the bottom of the bowl. The condition of the bowl is negligible too. Most likely your issue will be over/under development of your dough. 

Does the dough from your other location pass a windowpane test? How about your new dough? Assuming your relative humidity, proofing box temperature, and oven temperatures are the same, its going to be dough development. Experiment with different mixing times until you find the sweet spot. Also, if you are scaling a recipe down, occasionally you'll need to adjust hydration levels just a touch.