Aye, you could make the lower air scoop a little bigger to get your battery as low as possible, I would lessen the amount of anhedral a bit as well. You could probably remove quite a bit and still look scale.
I also agree with the glide test being the best way to find your CG. You are going to have a lot of body lift so your CG is probably going to be a lot more forward than a usual guess.
As far a the uptrim, it will most certainly need it as it will only fly with a lot of AoA naturally. I would not try to fight it. Keep your wings planks, if you make them high lift airfoils your CG and CL will do crazy things at higher speeds.
Nice pull
@Namactual. I've downloaded this pic, and was thinking "Space Flight Control" versus "Atmospheric".
With 1 pusher adding a dual horizontal and vertical thrust vector mount you can get "Pitch" and "Yaw" control assistance from the prop. But with 3 EDF's, things get a little... interesting.
Pitch downward comes from increasing power from the single upper engine, and thrust vectoring. Upward pitch with increasing the 2 lower engines power or thrust vectoring.
"Yaw" is met with Pitch added if you only use Differential thrust, and therefore takes more thrust vectoring into account.
"Roll" must be attained using eleron and possibly rudder to achieve. Unless you can program in three angle thrust vectoring to force Roll Spin from the 3 nozzles.
I can easily see where she'll want to fly upside down, and on her side would be... interesting to say the least. Pattern flying in competitions would take so-o-o-o many flight hours to get her to settle down into some semblance of balanced flight.
As mentioned previously large slow floaty, park flier might be the aim, but like the King Sword, She'd love to be a speedster.
Pusher versus EDF would end up being two different animals all together. She'll need three things I see to even think of making her flyable as an EDF machine. I'd suggest 12 blade high output EDF's. Thrust Vector nozzles a must. Thirdly, gyro stabilizer electronics. Shifting the batteries and ESC's into the cockpit floor would be another thing, hopefully shifting the CG into a usable point. She'll be tail heavy with the 3 control planes aft, as well as the engines.
Actually making this bird stay in the air is either the old "Throwing a bullet down range" style of flying, or the always interesting "Build, Crash, Learn, Build, Crash, Learn, Repeat" technique. Actually just putting 3 tubes with props in them, and adding a long tube nose, then 3 control surfaces and getting your head around getting that to stay in the air before making her look like an actual semblance of a Colonial Viper might be the trick.
Heck, I have even thought of controlling the winglets and rudder of the Mark I with internal driven servos driving landing gear wire through the thrust tubes, bent inside each control surface to move the whole plane of each independently.