Forming a Pvp Team

hi guys,
our guild is called Diviners Fellowship. currently, we have about 50-60 members in the guild. quite afew of them are lvl 20 and lots of them are on the way there. recently, i had discussed with the officers about setting up a pvp team. but we didnt really have a clear idea how to go about setting one up. the main problems that were discussed are:

1) if we were to setup a Fix set of pvp team.. not all the "fix" members might be able to make it for the gvg/tomb practice.
2) we were then considering to have reserves, but telling the pvp team memebers that they are the reserves is not very nice as we discussed
3)Time zone difference.
4)so alright, no Fixed set of pvp team, then its going to be very hard to coordinate the group (in terms of strategy)

if someone could enlighten me on how to go about setting one up and managing a pvp team, it would be greatly appreciated

This is quite tricky problem. If it isn´t done properly, bitterness might appear in your guild. This was also one of the reasons why I left my previous guild - aslo with about 60 members - (others were rude to us that we made pvp team and they didn´t and no officer responded to our suggestions).
I suggest few following things :
For the first time, you have to declare objectives of the guild : if you want to reach top100 or just play GvG for fun. You are trying to make PvP team so I suggest that it will be the first objective - to the best as possible. Tell this to all members as a reason why are you trying to make pvp team. Tell them that in PvP is required extreme coordination so the best is if the pvp squad is still the same.
But (and there was a mistake from officers in my previous guild) other officers in your guild (assuming you wil be the part of PvP team) must keep trying to promote activity of other members. They have to know that they can rely on you and other officers. You must still remind them that they should go to Tombs with other guildmates and when they are good they can possibly make team no. 2 and play GB as well. You have to tell them about the reasons of build and why is the team made of random classes useless.
When you have more good PvP players, you can then combine them for GB, Tombs, etc., so everyone is satisfied. But the key point is that they need to understand that they have to train. And I suggest that you should be straight in this point.

Edit : to the reserves : When we are recruiting (only few people for our guild, making it strictly small because we don´t want to allow what happened to us in our previous guild as I mentioned) we tell them that it can happen that they will be reserve and if it bothers them they should find another guild. There is nothing polite about that, saying it straight is the best thing in my opinion.