@chadholdorf - having the ball valve will let one work on the master valve without turning the water off to a larger part of the water system. Even if you need to cut out the pipe to fix the leak I think you could limit the cutting to elbow in question. One would need to add a coupler and a small piece of pipe on the vertical run to get the new elbow down to the manifold level.
If you want to replumb more of the setup so there won’t be a coupler right next to an elbow, then I’d plan ahead and have enough vertical run (at least 14", I’d add another couple for comfort) to put a flow meter in at sometime in the future (would require a Gen 3 controller too - if you don’t have that).