Koffar, if you generally camp in the high 30's then a 30 rated incubator with possibly an ounce of over stuff in it should easily keep you warm enough while wearing proper clothing. But everyone sleeps differently so you are the one that has to ultimately make the decision. Are you a hot or cold sleeper? But just for reference sakes I've taken my 20 incubator no over stuff into the teens. The incubator is a mighty fine quilt and has served me well for several years. It is certainly top notch gear. As for weather an UQ can be to warm or not well if you do get to warm their is always venting the UQ but if you back pack then your carrying the extra weight of the heavier UQ that may not be needed. If weight is not a consideration then I personally would go with the 20 but if you are weight conscious then I'd give some serious thought about getting the 30 and even possibly looking into the phoenix. I have no experience with the super shelter so I cant compare but I hope this helped some
Sometimes I like to hike and think, And sometimes I just like to hike.
Hiking is'ent about waiting for the storm to pass its about learning to hike in the rain.