What is the official accepted protocol in a situation like this?
I don't think it's an across the board expectation for bosses to give angpows, even if you're Chinese. It really depends on your company's culture. Ask around and see if the other bosses are planning to because if they don't and you do, you might 'spoil the market' and affect your working relationship with your peers. If they do, ask how much and match them.
Some companies have a practice of paying the month's salary in advance just for that month, so people have more cash to use for CNY. Depending on when your company's pay day is, this might be a goodwill gesture.
Another goodwill gesture is to give Chinese employees the afternoon off on CNY Eve. This will give them more time to prepare and cook the big dinner, or get dressed if they're going out for dinner.
In smaller companies the bosses take the staff out to dinner (night before the Eve, never on the Eve itself as that's reserved for family) and give food items or commemorative coins or oranges at the end of the meal, rather than cash.
If you do decide to give out angpows, a useful tip is to prepare more than you think you need (in smaller amounts if need be), since once people like cleaners, security guards etc hear you're handing out angpows, they may just 'happen' to cross your path and you'd have to give them something too. I wouldn't fret about the exact amount as long as it's in multiples of two. I seriously don't think it matters since it's a token, unless of course your employees have been spoilt in the past and expect a certain minimum. Ask a long-time employee whom you trust what the company norm is.
Hope that helps. Good luck!