I have always purchased on Ebay. There are a couple local dealers but they are 30 minutes from my home and I can brouse a huge inventory on Ebay right from my office. Moen, I think you got a great buy on those Sil -S proofs. I still need to fill the 05 and 06 holes in my Dansco 8125. Where do you thing people get theirs? Is there any other source other than people breaking up the proof set and piecing it out?
They only come in proof sets and dealers break a lot of them up. I watch ebay sales all the time. You can get some good deals. The seller I bought the proofs from was running 2 sales for exactly the same items at the same time. I tried to buy both sets but couldn't get the second one before it ended. You should have no problem finding the last two coins.
There are lots of places online, Here's one that looks good: http://www.collectoronline.com/10074/InventoryPage/1625216/2.html
I have some extra proofs and some extra ms business strikes. What holes are you trying to fill? Maybe I can help.
Please take trades and such to PM's as trading offers will just have to be edited from this forum Speedy