This is a doomed Venture from the Start. The moment you begin fielding "defense" ships, you will be questioned as to why then accused of not being neutral and then you WILL be targeted.
Then we get down to the RP side of things. First off, don't even think that the amount of in game ship's will count for anything should you try to get involved with plot. As we saw with the Annex of Gran Canaria plot line, as far as the story goes, Zoner's do not have any real fire power to push back anything, they are not a united front, nor ever will be. There have been many, many, many, many, many attempts at some sort of Zoner Fleet, pretty sure your not even the first ZDF and they all failed. Mostly because the community doesn't want one and because you WILL BE TARGETED just for the LoLs.
Zoner's are viewed as pacafists, ones who shouldn't have capitol ship's and other groups will take issue with you fielding capitol ships in what they consider their space.
As someone who tried to enforce NFZ and Zoner law's for years, as OSI Security Lead, then the Confederation of Freeports Leader and then as part of Velvet, the reason Velvet and myself essentially gave up is because of the amount of OOC and IC drama that was caused by those abusing it and the fact alot of Zoner players are not PvPers so we would get out played and couldn't enforce the NFZs at times,. The biggest reason of all was a chat i had with a Story Dev who essentially told me that Freeport Administrator's actually have no power over the NPC stations such as Freeports. So i made the decision that the only stations we would actively protect are our own POBs.
A Zoner Defense Fleet is a taboo in the server. If you REALLY want to try this, keep to using Snub craft and maybe gunboats because I guarantee the use of Capitol's will be your down fall.