Parnell,
The river is not too wide and very smooth. You would be fine in the 16. Hell, we went over 100 miles on Friday last year and saw maybe 5-6 other boats. No wakes and flat water. We did pass the mother of all tour boats coming into Chattanooga on Sat last year that threw a hell of a big wake, but everyone did fine. In other words, the 16 or GT would do great.
Considering your GT is my favorite Donzi of all time, I am sure your 16 is equally as nice. Can't lose either way. 
John
Last edited by Donziweasel; 07-23-2011 at 02:52 PM.
1979 Criterion
2007 G3 W/ 90 HP Yamaha Jet Outboard
Jackson Hole, WY
540 Abuser
"What does a man have to do to get a RV like Poodles?"