Hok's kandy basecoats are actually a combination of kandy and pearls. With the pearl added it covers fast (or aleast faster) than a straight kandy but it still resembles a kandy not a pearl.
Kandy K's when mixxed with interclears are much more transparent. When you keep laying it on it will turn black, where as the bc Kandy will turn more opaque.
As far a spraying KK's straight w/reducer I don't know if you can do it or not, I've never tried. Maybe someone else has tried it or knows....anyone?
Which one is best for flames?....their both intermixable so there is endless colors...and it depends on what type of flame effect your looking for....BC K will give you a more solid,flakey,opaque color. KK with interclear will be more transparent and give you more flexablity to control an effect. .......the combinations are endless, ...mix BC k w/inter, tint BC K w/KK....blah,blah. Look at Scott's examples. He lists what used for paints and that should give you the idea