Bulk String storage with rubber (EPDM membrane)
I came up with this about 6 years back. I get bulk strings #20 each in many varying gages. The Jig is a chunk of ply wood with a large hole cut-out. Then stretched over this with a stapler is a sheet of rubber material, I used EPDM membrane which is used in construction, and then this is mounted to the wall. This stretched material gets layed-out in a grid maybe an inch and half square, then small 1/4" slits are cut to accommodate a batch of say, 32 gage wound strings. Just push them through and they'll hang there waiting for you need....
good luck greg