I think that the embedded image option should be the rolling 30 day since it is just a single number.  And Shazam, I am right that javascript is not easy to add to a signature and it needs to be an image for the most people to embed the value?

I'm all for transparency; however, promoting the rolling # first makes sense and then providing the MTD # as well would probably be the best in my opinion. This would not only promote the pool in the best light* but also provide full disclosure of the current month numbers.

* It's rare that people slurp their soup/spaghetti on the first date!