Angelika Monks, a very well known quilter over here, and a friend as she happens to live near me recommends this to all her quilters
http://www.ebay.co.uk/itm/54-White-C...item2303700a5c She does hand and machine quilting and says for hand quilting it is superb. I have used it for a couple of years and have bought it in various weights, you can also get a superb cotton one and it is a fraction of the price of the normal batting. Although it says only dry clean I ignored that and my quilts which are heavily used wash superbly with no problem at all.
I am afraid I must agree with the other ladies I wouldn't use felt on a quilt that has taken me so much time, I would rather use something like the above.