Short words like Very, Most, or Pope are not abbreviated.
However, in the title "Very Reverend" the "Very" is abbreviated as V.Rev.
All of the above titles (in Mr Y's post) can be and are usually abbreviated; however, the honorific titles (His Eminence, His Holiness, His Beatitude, etc.) are usually not. Those titles should be used in conversation when speaking about
Hierarch X or Y, and most definitely as the means of directly addressing them. There are similar honorific titles for Priests and Deacons, which are theoretically the way we should address them (even though, according to some books in Greek that I've seen, "Father" is appropriate for all three - Priest, Deacon, and Bishop), although they are not used in practice (I've had a Metropolitan's Deacon correct me on this - "only the Bishop should call his deacon "Deacon," and to everyone else he is "Father").