Sounds like you are getting some pretty good advice.
One of the things I picked up on from watching Cesar, to let the dog know they are not doing something you are happy with, is to put them on their side and make a claw with your hand then use that to press against their ribs. It's a natural thing for them, you are replicating their mother nipping their sides to tell them no.
The few times I've had a need to use this on my dog it has been amazing, once he realizes he is down and "the pack leader" has his ribs he calms down right away and looks to me for direction. All with less pressure then I use when I give him a good scratch/brush during shedding season(if that ever really stops, lol).
Only let her up after she has completely submitted(breathing changes, muscles are not tense, etc).
You might try this at the next lunge/growl/etc.
Putting them on their side can be overkill, just depends on how co-operative they are being. For a fight I certainly would, but near each other on a leash and only a bit of a growl for instance, you might be able to achieve much success by just tapping the ribs with your "claw".
Think about it, if someone pokes you in the ribs, it certainly gets your attention doesn't it?
Good luck!