Hi Gypsyjohn, follows a link from a previous saddlebag install.
I got the Musette bags from Amazon.com. search for "Fox Musette bag" its sold through Amazon By Andrew Christian. The size that works is the small size which is (12x12x6) $9.99 Each + $5.49 Shipping. (I went to Tap Plastics a California Local Franchise and got some Styrene cut to size and had the same glued together (making a box) using their special glue, I'm sure any plastics shop can do the same for you. Also do a search for the same bags installed by "RAV".
http//www.enfieldmotorcycles.com/ forum/index.php/ topic,14803.0.html
The clearance of the bag on the muffler is a little over 1 1/2 inches, the heat does not affect the bag. attached are a few pictures.
Note: The actual dimensions of the bag are a bit smaller by approximately 1 Inch.
Cheers,
Mark