I know this is an oft discussed topic and I apologise for any repetition. I have already searched the OM forum history but haven't found the specific answers I'm after.
I'm trying to decide upon my sleeping system for a trip to Aconcagua and Chimborazo for Jan 2013. I will almost certainly be taking an exped matt and likely to be the Exped DownMat 9.
The bags I'm considering are per the table in the message below.
I'm really looking for something that has a rough temp guide of between -16c to -21c. Cost isn't really an issue but weight is. I don't want anything that weighs more than 1300g.
I've ruled out Western Mountaineering, Feathered Friends and Valendre for reasons of cost and/or appropriate product but if someone thinks I've missed something specific I would be keen to hear. I figure that if I end up spending a large amount (over £400) I would rather have the PHD Hispar 600 as PHD are local and I like their kit.
Does anybody have any experience of any of the above and is there another bag that I have missed? Does anybody know the length of the regular Hispars? They only list what height person will fit in them.
The Modular Option
Also, I am considering taking my Arc Specialist (good to 0c) and Quantum 450 (good to -10c) to put one inside the other. This won't be the lightest option (approx 1400g total) but is the cheapest as I already own them! It is along the lines of the PHD combi idea, which makes rather surprising claims (though I trust them) about the effect on the Combi TOT.
It would give me obvious flexibility, which would be good given that Aconcagua will be the coldest place I go and only 4 or so nights of that would be spent at really high altitude. I would/could combine it with sleeping in the the PHD Minimus Down Trousers and down booties, plus my down jacket (a Yukon) if really needed.
What do people think and has anybody done anything similar for Aconcagua or any other similar height/conditions mountains?
Thanks for your help.