Answer 1

I like silhouette levels, but you could take steps to make the dust easier to see.  It's not impossible, but still far from pleasant to try and spot the leaves.

One thing that can work is making the really dark stuff be layer 20 (cover all layer 19 with layer 20 tiles), and then letting dust and dustblocks poke through on a brighter color on layer 19.  There are several example maps where people have done that, like this one: http://atlas.dustforce.com/5428/almond-haze