If you think about it you have more potential to find silver in Strings and Sons wrappers. Why? Because more coin providers use them: Loomis, Garda, and Dunbar. Brinks is the only one that uses it's own wrappers.
I thought about explaining all of the factors involved to help explain how to determine which is the best to order from in your area, but it was getting quite long.
In simple terms, it's like gem / gold / silver mining, well drilling, etc. You have to drill test holes, and systematically determine which area will be best for you. The big difference with our hobby is that our resource we're looking for is constantly getting replenished. And it's like metal detecting jewelry on a beach - some beaches get more visits by more rich tourists. Some geographical areas of the US or Canada will have more older silver coin.
Another major factor is how many searchers there are searching the same supply, and/or dumping into the supply you are searching. If the majority are dumping into the supply you are searching a more diluted supply.
Personally Garda serviced banks are the only ones in my area that will order halves for me. And I've had some great finds since I started a few months ago. No Brinks serviced banks or Credit Unions will order halves for me.
You just have to order boxes for at least a month before you could start to determine if a source is good. And higher volumes of searching will give you better data to analyze.
