There are a few decent products,but remember, 100% pure tung oil is idffernet form most commercial products..
the ones you often see are mixed with poly and varnish resins..Like waterlox.
100% pure requires multiple coats..
so I recommend a sit down with your customer...and control sampling..say 2 coat...4 coat.etc..and get them approved before you price.
Maybe you can steer them to Bona Indoor oil finish or Rubio monocoat..these are 1 coat applications..
5500 sf doing 4-5 or even 6 coats will be pricey as hell.not saying they dont have it, but maybe they aren't understanding what really will go into this.
Old masters makes a100% tung oil..as well as others..you can google and get what is accessible for you..
this online store is great fro wood working and floor finishing..has alot of products..
http://www.woodfinishersstore.com/searc ... y=tung+oil