Try quads! Don't worry about accuracy, at that height, it doesn't matter any more. Obviously, you'll be good at catching upside-down clubs if you are even thinking about 9 or more. The point of 4 spins is that you get more time between throws, which is the most needed commodity beyond 9.
One little tip, stay fairly close together, no more than 1.5 times further apart than you would be for 6 club passing, but be very concious of keeping your passes short. There is a strong tendency to throw them long.
Another tip, wherever your clubs go, follow them. This means that if you accidentally throw a club long or short, high or low, the subsequent club should be thrown exactly the same way, then slowly work back to the proper position. Otherwise there are a series of different throws, which are much more difficult to catch than a series of throws which are all wrong, but all the same as each other.
Look at the top of the arc made by the passes. Your passes should be at the same height as the incoming passes, and they should be no more than a meter across from each other. There is a tendency to make your partner reach outside in numbers passing.
For 11 clubs, the 6 club start is difficult. One way to do it is to launch all three clubs from the right first, then hand the three clubs in the left hand over to the right in a bunch and then launch those.