84 at the waist is the new almost-fat
Seriously (again), the ski that was designed to do exactly what you say is the Phantom Crystal Ship 160cm. Skip the 180s - see the discussion at TGR about them. In general they are a total riot in trees & tight spots. I like them for general messing around as well - they make it worth mining for even a few turns of soft snow. The circumstances I've found them challenging have been boilerplate, breakable crust, and mashed potatos. In the latter two, the challenge comes when the tip gets under the surface - it is so broad that it can be hard to bring to the surface if running at all flat. On boilerplate thay are hard to hook up - and when they do, they can be mighty snappy about it (this can make for comical moments). And forget about big arcs under most situations. On the other hand, they are soft & usually pretty smooth. Make anything soft 5-6 inches or deeper "bottomless". Float over cutup, etc. Turn on a dime. If the groomers are even moderately soft, they will slice total rails going to/from- just for fun.
They were expressly designed for New England dense/steep tree skiing (the website video is too generic - does not do them justice in their real element). Given your stated goals, what more could you want? Some of the other skis mentioned are very versatile, however the Crystal Ship is totally in its element doing what you are asking for - even out here in the PNW.