I'm currently thinking about my next setup. Since I'm traveling to warm, mosquito-ridden places mostly with a 3/4 length underquilt, I need to be safe from underneath. Now, I know my double layer HH is safe. I would still like to try out the most lightweight double layer solution possible for the next setup though. So what is your experience, are any two layers sufficient to be bug-proof, or is there some sort of threshold concerning the strength of material?