lol skeleton key...
i want to say my 14 year old self would really want a green on purple wheel but lets not kid ourselves i still want that now
the green on black is definintely more tasteful
do the coloured formula feel different to the main ones? I noticed on Bones STF the colored wheels felt significantly stickier (not sure if they were same duro though) the white ones i have feel so damn light and plasticy vs. the black ones feel heavier and more solid
I think the technology has now come far enough that any of the different coloured Spitfire wheels still feel the same in terms of hardness, slide and longevity.
From the half a dozen sets of different colours I have had / still have in used sets in 99 duro, be it the solid single colours or the mix n match or even swirls, they all seemed to be the same, but like you said, some others have definitely felt like other wheels were harder or softer in different colours.
Back in the day, people would often get certain colour wheels if they wanted softer and others if they wanted harder because some of the dyes really did affect the performance of the wheels.