It depends on how powerful Rand is. Essentially he's the Creator's avatar. There are potentially no limits as to what the Pattern will do to protect him, or alternatively, what he can do with the Pattern to allow him to face the Dark One. Maybe he needs no one. There's really nothing that states that Tarmon Gai'don must be balanced and fair. Rand by himself might be able to fight the whole of the Shadow, depending on what he can do, and considering he's got the most profound effect on the Pattern of anyone who's ever lived, it could be dramatic.

That said, I don't think it's a waste of time to get the White Tower behind him. They spend a lot of their time squabbling, but I think any channeler army is very valuable. One Sister is as dangerous as a hundred Trollocs, and she can easily face a Myrddraal, which almost no non-channelers can manage. Groups of women together can be devastating. They also seem to be some of the more educated female channelers. They know more about saidar than most other groups, so they're probably the best Rand can get from that side of the Power. They're also a group that is almost completely devoid of darkfriends now - so that could make them trustworthy, which is very rare for someone like Rand. If I was Rand, I'd make some effort to get them behind him, even if it took a little bit of charm from his side. I'd place them high up on a list of his stronger allies, alongside his Ash'aman (assuming most of them aren't dreadlords by now).