I just installed the DX6 in my Sherman. Everything worked fine. I use the trim tabs per the instructions to fire both the main and machine guns. I have programed the DX6 in my Tamiya Tiger to use a toggle switch to fire the main gun and not have to mess with the trims in combat - as shown on the DAK site. Here is a link to Doug Sharpe's article

http://web.mac.com/ethandunsford/DAK2/Radio_Room.html

The Pershing is the tank that require you mess with the trims before it will move. Nice safety feature so you don't "fly" your tank off the work bench. I haven't put a Spektrum radio in it yet.