If you want something thin, but with richness, oomph, and firmness, check out the Bluechip TD 35. It is only .88mm, yet it is a very firm material without much give. Despite that, it seems to glide through the strings quite easily (does not impede triplets/trebles), and stays very firmly in hand, with a cat's tongue type of texture to the grip. I find it gives a better tone than anything else I've used, and I use it for both mando and cittern. They are expensive, but they don't wear down like other picks, so really it isn't much more money in the long run. I've stuck solely with these picks for the past few years, and don't care to use anything else.
http://shop.bluechippick.net/products/TD35.htmlSorry, it doesn't answer your Mick Moloney question, but I think the Bluechip TD 35 combines the best of both worlds, as far as thick and thin picks goes.