The OCLC Cataloging Label Program can import labels in SP1 format from a text file.
File specifications include:
Label examples with column and row numbers included:
123456789 1 PS 2 3525 3 .I972 4 G6 5 1984 6 7 8 9 0 1 2 3 PS 4 3558 5 .A64438 6 I38 7 1997 8 9 0 1 2 3 4 5 GN 6 400 7 .E85 8 9 0 1 2 3 4 5 6 7 F 8 294 9 .S2 0 B48 1 1994 2 3 4 5 6 7 8 9 LB 0 1025.2 1 .K7x 2 1504 3 4 5 6 7 8 9 0