Hi again – just got a chance to try it! Very nice. It's too cool to see my idea suddenly become real.
I think there's a little bug though. My first attempt, I typed a number in manually rather than using the slider and the generated colors were quite different, I think it's got something to do with the slider value being just [5] rather than [+5]. So I tried +5 on a different color, which seemed to work.
But I think a variable isn't being reset or something, as further experiments would cause an odd second color (Which then incremented correctly). Example, a deep purple swatch I have, 96,93,31,21 … I try brightness + 2.1… 2nd swatch is 69,64,63,63, a cool dark gray. Then 3rd, 4th, 5th, etc. swatches gradually brighten as expected, but starting from that dark gray.
Something else, but not as important, is it reaches the end of the loop and draws my original swatch as the final color.
Anyway, if you get a minute to revisit it… I hope we can iron out whatever's happening. This tool would be tremendously useful to me.