Let me add to your description of the "Loci method" (also the basis of ancient Ars Memoria). You are using spatial memory (which is probably the evolutionarily oldest/most optimized) to piggyback the data you want to memorize.

There is an easier way for people who don't do that well in visualization. Divide a sheet of paper into areas, then write down notes on what you are trying to remember. Make areas somewhat irregular, and connect them with lines, squiggles, or other unique markers. When you write them, and when you look them over, make note of their relative position - formula A is in the left top corner, while formula Z is down and to the right of it, just beyond the spiral squiggle.

For a lot of people, this works just as well as Ars Memoria, and is a lot easier to learn and execute on the fly.