Neither is Garland...everything is in flux, so it's going to be the question of just how far Garland will go for his house. As I have said, the Tyrells have a lot of money too, they could muster almost 100,000 men if they paid for mercenaries, and it wouldn't be difficult for Garland to fight a long war against the Lannisters. The problem comes when you add another house, one way or another on either side. The Stormlands, Dorne are the two that would have the greatest influence in a war like that. It's big decisions that have to be made, Garland is not an experienced man, BUT he is one that has one hell of a lot of power to wield. And remember, the family pushed the Lannisters out of power once, so it may be that Garland sees the Crakenhalls as a real match for that now. At the other time, he could BACK your character, but it would be such a fragile alliance, who knows what could happen. It would throw the Targs out, most definitely, but would Garland be happy if he was told for all that, he was just a Hand once more? 

I love contemplating this, it's all perfect GoT stuff :)