I'm currently building a Senior Telemaster. It is an 8' span plane but rated for a .60 size engine. I'm covering with fabric and dope and chose a dacron (like SIG Koveral) from the Aircraftspruce website. It's their lightest, non-certified fabric at 1.8 oz/sqft. It costs $3.25/yard at 60" wide. They also sell both Nitrate and Butyrate dope and all of the associated thinners and retarders etc in Pint, Quart and Gallons.

the link to their site is www.aircraftspruce.com. Look under covering materials.