I think I would reconsider trying to run a sub box that has 150-200 amp capacity, and instead, run a single circuit that will cover your demand, and use a receptacle / plug for your equipment. Since you are a one man show, you won't need more than one piece of equipment at a time. It will be MUCH cheaper to run a 50-60 amp circuit than a 150-200 amp, both in the conductors, the breakers, switches, etc.