Chad, your setup seems to be what I will use but only down to 0 F. B/C I'm starting with a bag good for only 20 F.
i.e. my WM Megalite (now overfilled by WM) EB Down Sweater and Theromlite Micro insulated pants.
I "need" some WM down pants and will likely get some this winter. Synthetics are bulky to pack, even for a pulk setup.
BTW, I think I'll try a VBL suit. Week long trips without a VBL make down bags wet. Don't ask...
Oh yeah Eugene, about that -20 F. bag weight - it truly is d@mn heavy and when in a compression stuff sack STILL has to be strapped outside to the bottom of my big Dana Terraplane because it won't fit inside the zippered sleeping bag compartment. Only my Polarguard 0 F. bag fits inside.