I have searched here and on Google for this.

If you have 5 foot San Pedro, can you take a cutting that's 1-2" tall, with cuts on both ends (as if it were a section from the 5' column), let it dry and scab over for a couple of weeks, and would these be viable?

Thanks.

yes

1-2" cuttings are possible,
but you'll have much better success w/10-12" cuttings

Most definitely Yes, small cuttings work. I have two 1.5 in cuttings i made last winter that put out a pup each in the spring after they rooted.