The bag (soft case) is 10 mm thick approximately, I do not know how well it gonna work as a warm case, but it will definitely give good mechanical protection while transportation. The 30" bag fits my guitarlele pretty well (Korala UGN-30: length 77cm, width 22cm, depth 9cm). The pocket can not fit A4 sheets without folding, but a file or folder can be placed in the main section under the instrument. Zippers work pretty well. Shoulder straps fit adult male in summer or demi-season clothes, but they could be not long enough to go with thick winter clothes. Anyway - pretty good bag for guitarlele transportation.
This is an excellent product, I got the 30" gig bag for my baritone ukulele. It fits perfect, well padded to prevent scratches to the instrument. Love the extra pocket to store things. Thank you ReCloud for an excellent business transaction, AKG