What hunting do you do? Do you mind bugs? If your in the bush and don't mind bugs then a tarp and rectangle of building weather proofing are lightest option by far. Get sil-net type fly. Silicon impregnated nylon. Tent will do far better on the tops. I have use a fly in pretty rough snowy conditions on the tops but you have to know how to pitch really well and will have to low.(not much head room)
I used to work guiding 20+ day trips and have spent months under a tarp
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