Interesting, seems like you guys layer up heavier than I do when active.
I'm about 5'10, athletic and 170 lbs and with a cap 2 baselayer, stoic wrath windshirt, and light softshell pants (OR Ferrosi) and I'm good down to about upper 20s or low 30s with wind when on the move (i.e. summiting a 14er in October). Add gloves if I'm scrambling or using poles - rocks and metal are big heatsinks. A headband can be nice too, but that's more of an 'extra' comfort item and it's a bit of faff, so I usually don't bother. Hats are too warm usually. I move up to a micro grid fleece like cap 4 when it gets colder.
Like Ryan, vests don't work very well for me - you just end up with cold arms, and I agree, 60g vests don't make much sense - use fleece instead at those weights.
I only like vests in really cold conditions when doing stop and go sports like skiing, when you already have a few heavier layers on. The lack of arms on the vest helps a lot with mobility. I use my 100g vest when it's around 0 degrees.