tractor-feed paper sizes?

Does anyone happen to know anything about obscure sizes of tractor-feed paper? We've now got the console typewriter of the PDP-1 at the Computer History Museum working correctly. It is an IBM Model B electric typewriter modified by Soroban Engineering for use as an I/O device. Soroban added an encoder and a decoder mechanism, using switches, solenoids, bails, etc. There was a bent leaf switch contact that resulted in incorrect character codes on input, and two stuck solenoids that resulted in incorrect characters typed. Anyhow, the typewriter will accept individual sheets, but it also has tractors for continuous forms. But the distance between the sprockets is approximately 13 1/8", which is narrower than the sprocket spacing of standard line-printer paper. A Google search reveals plenty of places that sell 9 1/2" wide or 14 7/8" wide continuous forms, but are other sizes readily available? Thanks! Eric Smith volunteer, Computer History Museum PDP-1 Restoration Project http://pdp-1.org/