All in "small":
Terramar merino bottoms, about same thickness as Cap 2, 5.3 oz. Often on closeout at STP.
Patagonia 1/4 zip LS merino top, older style, about same thickness as Cap1, 4.6 oz. Very soft, zips up to mock turtle neck.
BC.com SS merino top, very thin, 4.2 oz. BC has replaced with similar "Stoic" brand, often on SAC. Fits snug.
I used to use synthetics which weighed a bit less for same thickness, but the stink was a problem (even after washing). To me, merino is more comfortable at moderate temps vs. synth--warmer when I'm standing, and cooler when I'm moving.
My capilene stuff was prob. a bit lighter for the warmth, but I never wear it anymore.