1. No I have never seen anything like that.
2. Normally the contract stipulates the number of hours a week
3. 42 hours per week is standard, although I have seen 45 (42 practically, the extra 3 was used to absorb the shift penalties).

Having said that, a lot depends on your employment role. If you are at a level of management that affects the day to day running of the company, you may not be entitled to overtime. At middle management and below you are covered by Swiss employment law which is quite restrictive on working hours, minimum breaks between shifts, etc. At your level you can only work a maximum of around 50 hours a week legally.