About the targets I actually use nowadays: I have made and used the perfectly spaced 86 step targets, where each step between the 0-255 values are an even 3. It didn't seem to offer any real advantage in making QTR profiles over the 21 step grayscale included in QTR—with the required difference between each L* step used for linearization it really made it worse when the install script creates its correct curve look up.
I use the 51x3 step for checking linearization and ICC creation. I am working on something now that might be better suited for the 86 step grayscale, but I don't ever use the 100 step targets—I've found that there can be too much variance in the actual readings when the scale is sliced that thin, and it is hard to know what is actually "off"‚ the print of the spectro... (even when using the 51 step target, which is why I average that one.) In any case, the 1% steps at the end of the scale might not offer any advantage in actually making profiles, but would just show you what is happening right up to that last 99% step. Those it is easy to see where the in between 1% tones would fall when graphing the 2% 51-step wedge as well.
Richard Boutwell