The reason I went with the Hilleberg Keron was just to avoid their problem of angled foot ends. No part of your sleeping bag should touch the tent fabric, whether single or double wall. Most Hilleberg tents have steep angled foot ends---Nallo, Nammatj, Akto, Allak, Soulo, Staika etc---and when conditions are right the inner yellow canopy will have some amt of condensation---ergo wet foot box of sleeping bag.
Double wall inner tent canopies get wet with condensation too, but nothing like single walls. I'd much rather have my sleeping bag touching my inner tent than my outer tent fly.