Can not answer the circle hook question.
But, I know why you are failing to hook the fish. The first contact the trout does is just to ‘stun’ the prey then it carries it 3-4m before swallowing. While being carried the trout is only lightly holding the bulley meaning any strike would likely pull the bulley out of its mouth. If you want to bully fish, you have to wait until the trout has swallowed before striking which would result in a gut hooked.