I'm looking for heavy bus and light duty driber?

That's right, you're thinking rationally. Because if you have personal transportation, your company will be very pleasant to travel around the city of Zurich. Here https://bus-service.com/18-bus-charter-zurich you can write to the manager about what kind of bus you need and discuss all the details. This company has a huge number of buses and they will offer you the perfect option for you. I used this service myself and was very pleased.