Time required to change a couple of pulleys

[pothole]

How long would you expect a specialist Porsche mechanic to do the following work on a 2.5l 986:

- Remove drive belt
- Fit new top pulley
- Replace drive belt
- Remove drive belt
- Fit new crank pulley
- Replace drive belt

So, I'm looking for how long it would actually take rather than how long you're likely to be billed for. ALso bear in mind I delivered the car with the cabin engine cover removed and the engine and drive belt already exposed.

Thanks