You may need several blankets if you are like me. I don't know how to stretch the stuff, which you need to and the headliner adhesive is not the best for it either.
It also shrinks a little so when you start off you cut it nice and tight in the square corners. Overnight you will find that those joints have opened up a bit since the material shrank.
As I said also, the material in the moving blanket in your HD may be different. It depends on who the local supplier is.
The one I had (past tense) is pretty thick like the original deTomaso material was. There were no HD's in Italy back then.