My advice to you, spacepain, is to come to this forum for advice before every game with your mates, so that we can enlighten you in the ways of exploiting cheesy tactics that exist only in unpatched-unmodded-Dominions, so after each ***-kicking be sure to explain to your mates how you would not have been kicking their asses had they installed the latest official patch and CB mod
Other than that, the most obvious tip I can give you has been mentioned already - F9W9 blessing on vans. With their high innate defence and the defence bonus from W9 they become almost untouchable and F9 makes sure they can pack enough of a punch to take down any common unit.
But even so, I'd say that in the end game, the vans pale in comparison to SCs, mage squads and summons, so you'll probably have to go for somewhat of a "rush" tactic to capitalize on their early strength. (though the wealth that the early rush will provide you should definitely make up for that. Just be careful not to get ganged up on!)