Currently running the EXO K4 2200, the Dryad Mini-Drey/Killdeer setup for "short" sits and the Cruzr XC for all-day sits, the Sladder and rappel for a climbing method, and the Latitude X-Wing for a platform. Layers are subjective as for temp, but I prefer a wind/water proof outer layer and puffy synthetic mid-layers for packability AND a GOOD base layer system. Also, good boots and socks suitable for your terrain, feet, and temp. The exception to the layering system is the physical stuff that I'm wearing in, it has to be fairly quiet, water resistant, "brush" durable, and somewhat breathable and/or able to be vented.
Early season it's closer to UL with a lumbar/battle belt setup with shoulder suspension and maybe a Sherman Pocket attached, and obviously less layers.
Every pound counts, but comfort for mental stability matters a hair more, and a pack that carries well helps negate the weight, and the boots carry you lol. I also usually prefer the pack if it's gonna be deep, because the deer isn't gonna come out whole...