Since my first trials with the actual Layla magnet were a big fat fail, I did as Passion4Polish at MUA suggested - first, I removed the magnet from the cap with an exacto knife, and then stuck it on a piece of flexible plastic (there's no need for using glue as the magnet still has a fair amount of adhesive left on it after you pry it off). This way I could bend the magnet so that it better fits the shape of my nail.
As with most (all?) magnetic polishes you'd better let your mani dry for A LONG TIME before applying your top coat. Trust me on this. If not, the metallic particles will bleed and diminish the effect. I think I waited around for about 30 to 40 minutes before top coat.
I also got Galaxy Silver, which has square silver glitter in a silver base. As with Glamour Lilac, this is one coat over a darkish grey creme base. The base colour will show through (at least) these two polishes, especially if you only apply a thin coat of the magetic polish on top.