I got a reply to my facebook inquiry as well. Sorry I didn't post earlier-we have all been sick here (except one daughter who is stepping up and doing all the chores for everyone else). Here's the reply.
Hi Gale, That was a ruler I did for a notions company over 20 years ago. We don't have any of the rulers or the instructions and the notions company has been sold several times.The short version is you use the second cut ruler as a "place holder" for a 1-2 inch strip width measurement or one of the angles marked on the ruler and then align a second ruler against it. You cut against the second ruler. I hope that helps.