The sewing machine is around Montgomery AL at the Twisted Spur. Yes all of my belts are doubled and stitched Herman oak. Go with whatever thickness feels right to you. I have found 8-9 lined with 3-4 to be my favorite or 9-10 lined with 2-3.
As far as price is concerned. You can always charge more, but think about this every item you make is a learning experience. If you are still new to this you are better to put out 10 belts at $100 this year and learn 10 times than 1 belt at $200 and only learn once. You can check out some of my stuff at dndleather.com for reference.