Chava
Do your sleeping bags zip together? Have you tried it? Zipping them together will keep you much warmer. They are undoubtabley synthetic to weight so much, that can be a good thing on long trips in wet weather.

I've used my 40 degree down bag in the Sierras at 28 and I was just a bit cool with my clothes on and my jacket over me.

Mosquitoes are a problem in the Sierras, tents are nice

I like a PUR camper filter in the Sierras, because its fast - so less time in mosquitoes by the lake.
Jim
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These are my own opinions based on wisdom earned through many wrong decisions. Your mileage may vary.