Has anyone ever compared the relative warmth of belay jackets on offer? I'm wondering how the different weights and fills compare against each other, scientifically? I know you can do fancy stuff with clo values, but that's as far as my knowledge goes. I figure some sort of maths is the only way that you can get an idea of how warm something is going to be, without trying them all out that is.
Basically I'm after a belay jacket that packs small, is relatively light and is warm for winter stances (and therefore fine for everything else too). Ideas are below, open to others too.
Arcteryx's Atom AR has various weights of Coreloft, 120g/m² through to 60. Jacket weighs 470g
Montane's Ice Guide, which I can get cheapo cont 210g PRIMALOFT ECO insulation to front of body. 133g PRIMALOFT ECO in arms and 170g PRIMALOFT ECO elsewhere. Jacket weighs 635g
Mountain Equipment's Fitzroy has PrimaLoft® GOLD insulation (100g body and 80g arms/hood). Jacket weighs 645g
Do Pataguchi not have something in this market? Who else? I find Rab kit falls apart these days.