What is the accurate market risk premium to use currently? (for the CAPM formula for example)

In my MSF program most professors are suggesting ~4.5-5.7% depending on the argument you're making.

"7%, always use 7%." - big 4 partner

A bit of background on this: that bastard would always drink coffee out of one particular cup. on my last week there, I did the following:

1. got hammered the night before
2. got into the office early the next morning
3. go to the kitchen and grab some saran wrap
4. sneak into the bastard's office and take his cup
5. got into the washroom
6. took a dump in his fucking cup
7. wrap the top of the cup in saran wrap
8. hid the cup in a remote corner/cabinet of the partner's office
9. packed up my stuff in my cubicle, sent out an email to HR telling them I'm not feeling well and can't turn in for my last day (I remembered to drop my pass at my desk).

In my corporate finance class in b-school we were told to use the 30-year bond rate minus 1%, since the long bond is a bit more risky than shorter-term bonds. But yeah, 10% is fine for the risk-free rate. However, do NOT use treasury bill rates or anything below 5-year durations since any standard DCF valuation will have a projection period of at least 5 years.

10% risk-free rate? which market is that in? 5y or 10y government bond yld (US, GER) should be fine. agree with the argument that duration should be >= 5y