Nostalrius Begins - Quality wow vanilla realm (1.12)

Hi, i'm going to start playing on this server, mainly to pvp. I'm planning on playing as a shadow priest on horde though and i know there is very low demand for them in raids, so i was wondering is it possible to gear up at a reasonable rate through pvp and using rank armor sets or does that take way too long?
My alternative idea is to just go holy and heal dungeons/raids until i have enough decent pve gear and then respec, but thats not really something i want to spend my time doing.
Any input would be appreciated!