Those are nice. I have been making them for years....... Been sewing since I was a little kid.
The webbing is really smart and much needed. May I suggest going with the 2" you mentioned as it will reinforce the edges so the edge of the barrel doesn't wear out the fabric.
Some of them I have made were done with what ever cool looking fabric I had laying about and then I lined them in Kevlar. Kevlar is easier to sew than the webbing and even tougher. Cutting Kevlar can be difficult though.
Anyone who can make these can also make some pretty cool tank covers.
Still trying to phone home