Make 1 increase - I used the increase described by Elizabeth Zimmerman Make a backward loop over the right-hand needle and in the next row purl as a regular stitch.
m-1 means "make one", I think. I have used it in patterns in which I knitted 2 stitches in the same stitch, first in back and then in front of the same stitch.
I like both offerings. In particular the yoke pullover. However, I don't see any sizing numbers other than S M L XL etc. I am a very ample and would love to know the sizing for the XL on both. Thank you.