I usually like to weigh each bank separately. The heavier ones have more silver in them. On a more serious note, we need to know a little about you to put you on the right track.
#1 Where is your crib(home)?
#2 If said home is in a big populous city, advice will be different.
#3 How hard do you want to work ?
#4 Are you willing to travel ?
These are just a few of the questions we need to know. If you live in a big city, you are going to have a lot more competition for the halves or dimes. Try a little experiment. Grab you a hundred bucks and pick out a street with a few banks(the more the merrier). Start at one end of the street and hit every bank asking for halves. You should have a pretty good idea about your competition after 5 or 6 banks. If the tellers all say you should have been there yesterday,that's not a bad sign. If you get a no or a sneering no, your competitors have pooped in your neighborhood. Then it is time to expand your search parameters. The harder you work at this addiction, the easier the silver is to find. Cheers, Jim