Wafflepool guy, from what you've been able to put together, you seem like someone I would trust to get this right. If you give it some thought and run it by some of your smart friends and associates, I am confident that you will ultimately come to the right conclusion.
I'm pretty sure is getting it right.
The luck statistic I've been asking for is not just display fluff. It lets people judge whether the observed earnings they are seeing are higher or lower than normal due to luck. That is important, especially for a small pool.