I just acquired a very interesting little reprint of the 1888 edition of Gregg's booklet--the original publication from Liverpool. Apparently McGraw-Hill reprinted these in 1971 and distributed them to shorthand teachers--I also got a copy of the letter that accompanied the reprint from George S. Deeg, III, "Shorthand Project Manager" at McGraw-Hill. It's a rather knowledgeable letter, and states that only 500 copies of this booklet were printed, and at the time only 9 copies were known to be in existence.
I wonder how many were reprinted in 1971 and how many are still around? (I bought this one on e-bay, and interestingly enough no one else bid for it. So I got it and 3 other books for under $10).
The title is "Light-Line Phonography: The Phonetic Handwriting".
It's a very crudely designed and printed booklet, and the most striking thing to me is the lack of clarity of the outlines. Also, ch and j are shown slanted, much more like modern t and d.
With this humble beginning, it's amazing that the system "took off" the way it did.
I'll try to scan and post some of it when I have a chance.