I just finished it.
I laid out a design that is about 1" x 3.5" with a black background, red lettering, and an image of about 0.6" x 0.9".
I printed ten copies of that onto one sheet of Avery Dark Fabric Transfers. I cut one transfer copy out and carefully laid it over a black patch. Well, actually, it is not a black patch. The fabric was supposed to be cotton, but the only thick black stuff I had laying around was black grosgrain webbing (which is nylon). The transfer was ironed on, and the heat really melted it into the nylon texture. In fact, the nylon was slightly seared from the heat, which blended the edges of the transfer nicely. I heat-seared the cut edges of the nylon also, just to avoid unravelling. The finished product is ready to sew onto clothing now.
The Avery 3279 package was $10 for five sheets, and I can get 50-100 transfers out of those.