Long Distance HellmouthFor this trick to work WW needs 3 souls and 3 corpses on shamblers, stones and a heavy that will totally wreck you if he gets to alpha. First the shamblers get placed 7" forward. Then they run into position like this:
Then you Teleport the heavy forward. Hellmouth the front shambler. Decide to pull my heavy and then pull the back shambler that cant move anywhere since it is in base contact with the middle one. Then you pull in the middle one and that kills him. Then another hellmouth on the back shambler and pull in both heavies. We now have a 8+3+3+3+1,2(small base)=18,2" in threat. Then a stalker sprint away from you or WW feat and you stand there with nothing.
The double heavy hellmouthSince getting one heavy into another is probably not enough to win you the grind a majority of the time. This is a bit more shakey and you need to place your heavies to do it the turn before. You can quite reliably get 16"(18" with lanyssa) out of two heavies.
The crux here is to let the heavy you pull shorter on your side deal with the heavy you pull the most on his side and vice versa.
The bad part about this is that you can't do this on the wormwood feat turn since they can't charge through forests. So if this is a feat turn you need to do the above trick but having 2 heavies in stones usually means you did not Teleport WW last turn and that is a bad thing.
ForestwallThis is simple. He has a spell that creates a 4" forest. Cassius can fertilize 2 shamblers to create 2 more forests and then we have 2 sentrystones with 3" forests on them selves. Totaling 16" forestwall. Every turn this can be on the table.
Hiding behind a colossalThis is usually something you can do the turn after your feat when people jam you with all their models. You put up curse of shadow and then strangle hold the collossal. Place your heavy in the back arc of it. Preferably with stones since taking a free strike gets you dead.(note as Hugo points out there are no free strikes with curse of shadows so no real need for the stones :D )
This is a way to get around the need to primal and one turn a colossal. You can do it over two turn if that is all they have left.