I have found my Holy Grail
I have just been sleeping in my new Wiggy's Antarctic bag with over cover bag.
Under Me I used my normal winter setup Synmat 9 DLX (for comfort and warmth) and 14 mm thick CCF pad (for daily sitting etc. use and safety if Synmat would somehow get broken). No hammock, simply sleeping on frozen ground.
Clothing was cotton pyjamas and fleece/windstopper cap. Before this bag, my warmest sleeping gear was Warbonnet Winter Black Mamba and Winter Yeti.
Temperature only -15 C (5 F), no wind, little snow fall at some point. No tarp or anything else - I could see the forest and stars!
Overtoasty warm WHOLE night. No problems with over heating related moisture at early morning. Even if the test was done in such a warm temperature there is no question about it: I can sleep anywhere, anytime in any condition Finland has to offer with this combo. (Hammock use report will follow at some point.) Lowest temperature Finland offers is somewhere bit under -40 C (- 40 F).
Usage of the two bag system is very simple. Open one zipper, go in, close one zipper, cinch three well laid down cords, sleep. And no need to adjust those cords after urinary break. Outer bag can be over your face if full coverage is needed without any anxiety about breathing or condensation near face, or it can be pressed down for the view.
Bag is big and heavy. 1) But there is no need for extra clothing in your gear list. 2) It gives a marvelous safety factor for solo trips (even if lost, exhausted, hungry and shivering from cold after ice broke under you at river passage, NO WORRY there is always safe haven to go and rest, NO WORRY for getting your down bag wet). 3) System is very simple to use. 4) There is lower rated cover bag to be used in cabins. 5) Common knowledge seems to be that Wiggy's will last your lifetime.
So, You can keep the DriDown or any similar invention. I will keep my Wiggy's bag (And my two three-season down bags, two down WB quilt systems for those times there is no canoe or pulk where to put The Behemot Antarctic bag system).
P.S. It maybe possible that I will buy a lower rated Wiggy's bag in future...;)