I'm not sure why I'm delaying getting out the inks, except that I am enjoying the tube paints so much. In the meantime, I did order a few supplies that seem appropriate. From Gamblin, some relief ink in Hansa yellow light to use as a primary color along with the blue and red hues I purchased earlier. Also some "burnt plate oil #000", which apparently is the appropriate medium to use with the relief ink, rather than linseed oil or Liquin. This detail came from Gamblin's online article "Monotype: The painterly print." Gamblin also provides good information about their inks on their website, though they offer no instructional videos.
Takach, the manufacturer of my press, also provides many printmaking tools and supplies. From them I ordered a set of small (narrow) specialty brayers designed for printmaking. I had seen these at a workshop several years ago, and had considered getting them for cold wax work. But they are expensive, and I never did. The finer work required on monotype plates makes their purchase seem more justifiable. Also from Takach, I ordered a set of Akua applicators, small squeezable bottles with very fine tips that are used to draw fine lines on printing plates. So soon, I will have more supplies and tools for my work.
Eventually I will have no further excuses for not trying the inks.