The 1964 Bear Archery catalog calls for a brace height between 7" and 8". This of course is a guideline. Don't get hung up if your brace is outside these perameters.
Proper brace height is an individual thing.
Sounds like your string has stretched well. It's time to twist it up very slowly and raise the brace height untill you find that magical spot where the bow settles down. It will be dead in the hand (least vibration) and will quiet down audibly.
Go slow, raise it an 1/8" at a time and shoot it a bit at each height untill you get the feel and sound you're looking for.
I like to do this before adding anything to the string like brush buttons, string selencers, etc.
Remember that your nock point will likely move around slightly as you raise the brace height so be diligant about checking it and keeping it constant.
Once you get it where you want it, it's a good idea to put everything on your string that you intend to use for hunting or shooting. Brush buttons, string silencers, etc all influence the way your bow performs.
Hopefully these added gadgets, make a good thing better. If not, take them off.
I shoot my Kodiaks with brush buttons only.
Trap