Joseph,
The option to use 6SN7 tubes with the WA6 by using the adapters are perfect. Their are many 6SN7 tubes that will accomplish your objective. The Sylvania 6sn7WGT would be an excellent choice or another less expensive option would be the WQestinghouse 6SN7 tubes and can be sourced form ebay.
Thank you for your reply and information, I will look into these Tubes/adapters, thanks again.