I am not going to say where but I knew someone that was a caddymaster at a high end private course in the northeast. He invited us once a year in early fall to play the course. He told us exactly who to tip and how much, and he always said "no more, no less".
Each caddie got $75 per guy, double bags, and each twosome tipped the guy at the halfway house $20.
Admittedly this was about 20 years ago.
Someone very well known was a member there and he tipped 300 - 400 every time. The caddies used to fight to get his bag.