Hillberg Akto. Light, sturdy. I used mine a lot, and up to over 6000m in the Pamirs, guess that qualifies as 4th season. The large vestibule makes it easy to keep snow out of your tents. The Soulo is sturdier, but not sure if you will really need it.
It may be heavier than single walls, but bear in mind that a double wall tent is warmer, and you can get away with a lighter sleeping bag. Less condensation means less wetness on your sleeping bag, too. The tarp-solutions work, but are not that much lighter, as you need warmer bags (for the same comfort level, that is).