I just got Delft last week, and although I love the color ( goodness gracious I'm in deep love with the color), it doesn't seem to apply as evenly as the other 3 I own. It seems to make my otherwise dry lids turn oily, therefore making it's application uneven and streaky if I'm not careful.
Anyway, I use:
Delft under blues/teals (so far).
Groundwork for neutrals, pinkish looks, purples (and blues, before I procured Delft)
Constructivist under greens and browns
Rubenesque, I haven't used for a look yet, but I suppose I'll use it for greens, golden and bronze-y looks, and some pinks.
I have to get Blackground now. HAVE to.
nw45-47 btw