Thanks very much for the reply, James.
18 point is pretty close to 1/4" so at least I think have that right.
I was hoping for some info on the best way to make the stencil itself. Using a sign cutter with the vinyl material and PC software. I've watched a few Youtube videos and I think I have the overall process down, just was looking for some hints on the details. Things like the materials used etc. The small characters and the "weeding" seems the most difficult.
I did finally I think decipher the date code scheme. I believe it goes like this:
Date code is in my case "B 11 03 0" which is March 11, 1970 second shift of the form working shift(letter, 2nd=B), day of month(2 digits=11), month (2 digits=03) and last number of year (1970=0)