I think that the amount of votes needed for a vote should be showed on the little information board on the right of your screen. (The board where it shows money and next rank etc..) It's not really necessary but it's easier to see.
I might not have made my question clear. Which specific server will have the vote party, and what would it be, since many servers have different goals.
Some gamemodes have vote parties, like prison and factions. You can see the amount of votes needed for a vote party be using /vp and my suggestion is to move it from /vp to the little information board you have on the right of your screen.