OregonMouse I have done the math and it looks like the best I can do is a 6.5lb base weight:

ULA Circuit 38oz
Tarptent Sublite Sil 21oz
Marmot Hydrogen Long 24oz
Ether Thermo 6 21oz
Total Big 4 6lbs 8oz

As you predicted, much of the remaining weight in my pack is extras which gets my base weight up to 16lbs or so. I think I can lower my expectations to a lighter pack but couldn't carry the necessary water for the Arizona trail with that setup. Upon looking at the Sublite Sil in detail, I think it will be fine for either the raincoast here in British Columbia or the desert in Arizona at altitude. Won't be cool, but will hold water!

It will cost me to buy tent, pad and pack anew, $500!!
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