Compare
(A) "If Anna was here, she would've known what to do."
(B) "If Anna had been here, she would've known what to do."
In (A), the speakers are currently considering what to do and lamenting that Anna isn't with them right now, because she would have been able to help them.
In (B), the speakers are discussing a past situation (we don't know how recent) where Anna's absence left them with no solution. The opportunity to do the right thing has now passed.
I think if you see the difference between the two, that will go a long way to helping you with similar constructs.
"If you (wear) a beard all the time, they (not recognize) you without it."
All the below are possible:
(A) If you wore a beard all the time, they would not recognize you without it.
(B) If you had worn a beard all the time, they would not have recognized you without it.
(C) If you were to wear a beard all the time, they would not recognize you without it.
(A) Can be used in a past sense, in a kind of confirmatory way: Given that you always wore a beard, then of course they wouldn't recognise you without it. But it can also be a suggestion for the future: if>then.
(B) In the past period referred to, he wasn't in the habit of wearing a beard, and therefore had no chance to pass unrecognised by removing it.
(C) More specific than the second sense of (A). Making a hypothetical suggestion concerning a group of people currently unknown; implying that at the moment he doesn't wear a beard all the time (or at all).
Think of how B perceives it:
B: ... think think think think think think think—Sorry, what did you say?
A: [blah blah]
B looks back and thinks of A's utterance as an event which is completely done, finished. Linguists call this view of an event the perfective aspect. Perfective aspect in the past is expressed using the past form of a verb, You said or You did say.
That event, A’s utterance, occurred at a time when B was in a state of thought which started before A's utterance and ended sometime after it. Linguists call this view of a state imperfective aspect. Imperfective aspect is expressed using a progressive construction; in this case, since the state lies in the past, B uses the past progressive construction I was thinking.
Perfect constructions like I have thought and I have been thinking express a state which arises from a previous event and is current at the point in time which you are talking about. Linguists call that time you are talking about reference time (RT). A present perfect construction has the present as its RT: it expresses a state which is current now, at the time of speaking. Since B is talking about a past event, his† RT is the past; in that context a present perfect cannot be used.
A past perfect construction expresses a state with a past RT, a state which was current in the past, so you might think that I had thought or I had been thinking would be appropriate here. But the perfect construction does not express a state denoted by the lexical verb (think) in the construction, it expresses a state which arises from the state or event denoted by the lexical verb. B is not talking about the result of his thinking, he is talking about the thinking itself—so a past perfect construction doesn’t work either.
There is more about aspect here, and entirely too much about perfect constructions here. Be careful not to confuse perfective aspect with perfect constructions—they are entirely different things.
† I make the appallingly sexist assumption that A is B’s wife, only because that’s how this conversation always plays out in my own household.
Best Answer
The main unreal situation is that he is not our boss. I would write your sentence as:
Had been is not recommended in this case, as acted is simultaneous with the unreality of were.
If however, you want to emphasise that he acted like a boss, but not because he thought he was the boss, this situation is peculiar, but let's say it can exist. Then you could either say:
or