Yah, it will work if you keep making sure the BB has food. You could put some fish food in to feed the BB. You may still get an ammonia spike if you don't stock slowly so the BB colony can keep up. Even better, why don't you transfer some of the established media into your new tank?
I agree, Assassins may be risky and there are other safer methods. You could also place some zucchini in the tank and knock off any wanted snails and dispose of the rest.