alright folks: its 
TUNG and not TONGUE oil.  

In regards to Tung oil make sure, it's 
100% PURE tung oil. There' s lotfs of "tung oil finishes" that are not tung oil. 
Tung oil needs to be mixed with mineral spirits. I use a blend of 50/50 tung oil and mineral spirits. Apply a wet coat, let soak for 20 minutes, wipe off excess and let it dry 24 hours before applying the next coat. Repeat until your have 4-6 coats of so. Afterward the tung oil will continue to cure (it takes a month of so for it to finish curing). 
Tru-Oil is a curing oil varnish.
Tung oil dries matte. Tru-oil can be shiny. 
Which is better? I think it's apples and oranges in regards to those two. Personally, I'd use neither as a bow finish.