Only theymos knows exactly the monthly allocation of sMerit for each merit source. It's very difficult to work out exactly just by observing sent merits since you don't know which merits sent were from source sMerits and which were from personal sMerits, and how much of a pool of personal sMerits the source in question has to dip in to. You can get a rough idea of who the biggest sources are by looking at this list: https://bitcointalk.org/index.php?action=merit;stats=topsendat

Sort of correct. Source merit is replenished exactly 30 days after it is spent. If I had an allocation of 50 source merits, then I would be able to spend 50 source merits every month. If I spent them all one month, they would replenish and I would have 50 to spend next month. If I didn't spend any in one month, I'd still have 50 to spend next month. So the number of sMerit which replenishes is based upon how many you sent last month, but the amount you can award in a single month is always the same as your allocation.

Keep me on the list, but it's a global scandal that you aren't a merit source yet. We should focus on that first.