I don't get the ones with such similar colors. I think I get them from CSUSA (plastics sanding kits) and sand down to 600 with paper so don't even use the first micro pad (yellow, as I recall). That leaves me with 5 distinctly different colors-orange, green. purple, light blue and grey, and that's it. I've done hundreds of acrylics with these and it's perfect. Going through all 8 on each and every pen would literally be a pain in the back for me.
But that's just me!
Dale