Helium Reg 19.5 down (850)
Versalite 20 down
Now, check the dimensions...
Helium ... 62 inches
Versalite ... 62 inches
Helium ....58 inches
Versalite .... 53 inches
Helium .... 40 inches
versalite .... 39 inches
For the sake of argument, the main difference (weight aside) is that the Helium has a wider Hip region.
And yet, people talk about the Versalite like its a slenderer Apache (which makes it warmer because those 2 bag other specs are practically the same)
and people talk about the helium like its a huge sleeping bag.
Im a short, skinny guy and when I tried the helium on at REI, i absolutely loved the room (i bend my knees when i sleep on my side, but dont require it so i would be open to a slenderer bag) and the hood was fantastic and actually when cinched up created the hole perfectly around my mouth and not my nose. But the word on the street is that this bag is probably too big for me and would not be as efficient as a bag with smaller dimensions. But when analyzed, can 5 inches only in the hip region create such a drastic effect upon me?
What I am basically doing is FISHING for someone who is skinny and short and has the Helium bag to tell me that they are just fine in it down to 15 degrees.
Oh, and the real reason I want this bag and not other 15's is because it fits into a S2S 10L compression Sack and is SUPER SMALL. havent tried the versalite, but ive seen its stuff sack full online and its has to be bigger then the helium in its stuff sack (which of course doesnt necessarily mean they both cant compress the same, but it does sway me)