Okay, I've got to say, the ratio is completely backwards for Admins on Battle vs Admins on Siege.
A single Admin can effectively monitor and enforce server rules on Battle. A few things can be missed, but mostly they have time while dead to spec players, watch for leechers, enforce the no delaying rules, etc. Even while alive, you've basically got coverage for most things.
On siege, you want a minimum of 2, one on offense and one on defense. More would be preferable due to there being very little down time. You just can't cover it all without being intensely active on an already intensely active game mode. On Offense, it is even more difficult than on defense. At least on defense you have 30 seconds of downtime when dead to try to be on top of things.
Of course, I mean actively admining. Passively you could do it alone if you rely on "i" chat and occasionally go into spectator to handle a report.
The next round of recruiting needs to come from the active Siege mode player community. I've already started to keep an eye out for regular players who look to be good candidates on NA so that I can provide recommendations. For EU I again nominate Karasu based soley upon his cool head on the forums (having never played there its all I got).
Let's get some names up in here so that when we get an official "Okay we will add some", we will already have a list to provide.