Yeah Kevin, I already noticed the new Viper has tendency to be tail heavy due all new structural reinforcement and for having the new main gear almost 1" aft the original location.....[sm=frown.gif] happiness is never complete right...[&o]
I'm going to use 2 cytoys pilots....instead of one, and also plan to go with all details possible at the cockpit...
Also, instead of using standard size servos for the ailerons, is better to use HS-5245 or similar size & weight servos. They weight half and are located behind the balancing point.
Regarding the way to secure the elevator and rudder servos, I'm not sure but have the feeling that you need a good amount of silicon glue to hold them in place....and this way is heavier than using screws....right?
I use screw in my previous Viper and the set up was light and removable. At the elevators I had the same problem you had with the hatch, but now I reduce the problem to 0.25mm....that can me solve making a notch at the under side of the hatch cover.
Also installing the turbine & bypass as close as possible to the nose side (with some small mods []) could be a way to.....
If you don't have plans to fly off grass field, then use 2 5/8 inches mains wheels instead of 3 inches.
If you are using Y harness (without matchbox) to connect the elevator servos, then try to have the split of the Y as aft possible to reduce the weight of 2 servos extensions all the way from the tail.
Installing the light system will also help to balance.
I hate the idea of carrying dead weight on a plane....[>:]

As per the flap issue.....if you want to drop flaps without having problem regarding speed or nose level, then mix it with down elevator. As said before I prefer not to mix mine....I just drop the flaps at about 3/8~1/2 throttle stick position.

Are you going to be at FJ?
I'm 100% agree with you,,,,this a a beautiful plane and never going to get tire of telling to Tam to make a BIGGER version with All scale details [sm=thumbup.gif][sm=tongue.gif]

Miguel.-