Insulated pants: Down vs Synthetic

Last winter, I wore 17 oz Exp weight Patagonia fleece pants over my 150g wool baselayer. Sitting around a snow kitchen, on a 3/8" CCF, I was okay.

This winter, I want to lose some weight over the Patagonia pants, and I'm leaning toward a synthetic pair, either the 60g polarguard BPL full zips on sale right now, or a MYOG pair where I'd double the insulation in the back for sitting purposes.

Does sythetic insulate better than down when compressed (e.g. while sitting)?

Would I be better served by looking at a pair of down pants?

My baselayer would again be 150g merino tights and perhaps a pair of 100 wt (7oz)microfleece tights for the really cold temps.

My region is the Catskills and if I'm lucky a trip up to the Adirondaks. If the overnight lows are predicted to be below Zero, I'm skipping the trip.

Edit: I'm also looking for these to boost the rating of my sleep system, currently a JRB Shenandoah quilt under a Nunatak Arc Specialist, which my research on BPL tells me should take my to about 20 degrees or so.