Merino sleeping bags

I'm going to make one or two of these for the newbie... can someone who owns a merino sleep sack please tell me what brand it is and if it's merino on both the outside and lining, or is one layer cotton? I've got fabric to do a cotton and merino layer, and had planned on making it merino inside, cotton outside, but just saw one on TM that was the other way around - which would be more comfy for baby? Ella sleeps in Merino leggings and singlet under her jammie-jims and I've found that on occasion when she's wet through her nappy, her skin and the merino are completely dry and it's only the bed and jammie jims that suffer. I imagine the same would go for the bag? Baby is due in summer but I'll make the bag for the change of seasons when I'll have probably stopped wrapping bubs, so it'll need some warmth to it - I still use blankets over that when it's colder though.
How is yours made? Thanks.

Gremlins have Mokopuna Cocoonos and they are merino inner and outer with cotton stuffing.