Totally. Everything improves with more images since that’s your palette for painting, so to speak. The ones I posted were with less than 100 images so you can definitely do better.
L*b was very slow, yes. It’s all done offline but I tend to like quicker feedback...
there is no perfect way to measure color distances, mostly because it needs to account for human perception of color and there are individual differences in color perception among people.
But you’re correct, generally that’s the space you want to be in.