I was doing something similar years back in high school. I didn't figure out the periods and commas as such, but there is one more way that I figured out. All my papers were double spaced, but the page layout was not set up that way. I would type the whole paper at 12pt. font, then change it over to 14pt. or 16pt., and go back to manually add in the spaced lines.

Like he noted in the video, the longer the paper, the better the results. I remember doing a research paper for an english class that I obviously didn't want to do. Rushed though and only had almost four pages, upped the font size on the blank lines and I magically had, close enough to, five pages.

Time consuming, yes. I would even try to eek out a little more by increasing the size of any space between words to get a little extra out of the process.