I'm going to try the idea I came up with in my sleep..and then it'll be over (unless it works and I come up on another sticky spot!)
If my scheme works, I'll be back to tell you all about it. There's a good chance that it's kind of a dumb idea..so I doubt I'll tell about it here if it flops.

If I wasn't planning on moving the bathroom, I'd probably go ahead and get a different faucet set now..but since I am moving it (and my other tub will use different faucet) I can stand to give up and live with wasting water for a while.
If I go ahead and keep catching the leak in the tub..and use it for flushing, I won't be wasting as much as it seems like.