Overview: The YouTube video provided will give full details but basically I constructed a rectangular Underquilt with a my own way of achieving a differential cut both length and width wise (I think both are helpful or even necessary) and a kinda prototype clew suspension although I can hang it with traditional incubator type suspension 

Steps: photos and YouTube video provide steps but you basically need to plan well first all dimensions to account for several things and then mark all that off then sew on baffles and shells together then stuff.

Materials: ARGON 90 and down from Dutch. A few other bits like 1/4 inch grosgrain - 1/8 inch shock cord - Mara 70 thread - and 0.67 mesh - all from Dutch.