you could by pass the alt bracket by tapping the holes like you said. the aussies have a factory bypass they use iirc.

have you cleaned them holes out real good? 100 grit sand paper can help, mine had some kinda varnish looking crap in them that i had to chip out with a pick, then i sanded smooth. never leaked. also lubed them o rings up before i pushed em in. you also need to make sure the top elbow is square to the bracket and lim as you tighten the alt bracket bolts down.