The cutting gauge can be used for measuring the rags and getting them to equal sizes.
Wrap a long strip of cloth around the gauge, working along it a bit like bandaging a finger but keep going backwards and forwards. Wrapping several layers deep will make some pieces slightly longer than others, but the difference won't be enough to matter. The only constraint is - don't wrap more than you can cut.
Cut the along the groove, in the gauge, with a pair of sharp scissors; a craft knife would do, but scissors are safer. There - lots of short strips, all more or less the same length.