I'm only a little darker than you ('bout NW20) and I had the same problem with Lightscapade at first, but after playing around with it I'm converted.
Try the following:-
- an all over dusting for a burst of radiance (as already suggested)
- use more densely on the apples of your cheek on top of blusher as a highlighter
- use as an under-arch highlighter (though you shouldn't get it too near your eye)
- with scoop or low necklines, dust some Lighscapade MSF over collarbones to enhance them and add a bit of subtle shimmer
Perhaps this next one's a bit weird and might not apply to yourself, but I absolutely swear by Lightscapade to soften and diffuse my (quite bad) dark bluish undereye circles, too: I start of with a quick smear of a yellow colour cream correcter on the circles, which I blend round the edges with my foundation brush, then I use a *slightly* smaller brush than I would normally use for powder to pick up some of the Lightscapade from a yellow-pink-whitish part of the pot (basically I avoid the blue/purple flecks as much as I can here, too much of these tones could make the circles look worse), and dust the underye area with that. This sets the liquid concealer and softens the look of the whole area. You just have to be careful not to overdo the MSF in this area as it's easy to end up looking too glittery, but done right, this really works, for me at least.
Lightscapade is my first MSF and it's a weird little product, but it's a definite winner and I will look out for more of these in future collections.