Would it be grammatical and idiomatic to use master instead of mister or would people think I am mocking them and therefore I am disrespectful? I have no problem sounding Oxonian or being verbose but I would certainly dislike being disrespectful and mocking.
I am not confortable using mister, sir or lord.
My problem with mister is that I think of being a mister as less than being a master.
My problem with sir is that etymologically it means senior, elder. From Senex.
My problem with lord is that I fear that using it would be mockery more than using master.
Greeks call Κύριε every person they do not feel confortable enough (T-V distinction) as well as God even though God is treated as Tu not Vous.
In the Romance languages they are more fond of using Senior derived words and not Dominus derived ones but it is not a problem calling people Dono/Dona instead of Senhor/Senhora.