First off, welcome! Glad you are trying trad. I made the switch a year ago. It's a bunch of fun, but give yourself some patience.
To answer your question yes, deepest point of the grip. Start at 7 1/2 and go up until it's quiet. The exact height will depend on your draw length, arrows etc...
If it's a 1966 then those are sweet little bows but some of the 58" Grizzly's can be loud.
Post a pic! You can't go wrong with a Grizzly. I own 11 of them. My wife bought me one and they just kept showing up ever since
I may shed a few.