oops sorry didnt read your whole post and just saw it was unfinished in the pics
The first thing I would say is that 8 inch props are a little bit small fora 500mm frame
Its looks like your setting it up to fly X configuration 2arms pointing forward rather than 1,
Have you double checked the motor connections
Front left to pins 3 running clockwise
back left to pins 9 running clockwise
front right to pins 10 running counter clockwise
back left top pin 11 running counter clockwise
you will be surprised how many people get one wrong and every thing goes pear shaped
Sorry, not enough detail on my part.
prop size, I initially bought 10x4.5 but was recommended to drop to 8". These makes the quad feather at under half throttle and produces plenty of thrust.
All props run in the right direction.
All props are balanced to within an inch of their lives.
All speed controllers have been calibrated
X configuration as you say.
Yes it's set right in Multiwii too!
Props on and running multiwii shows really flat sensor output so not much vibration getting to them.
R.E your question about the sketch, It was already set to 0xd0 but I will check it again.
I'm tempted to buy a different controller and try that but that would be giving in and I'm too stubborn for that.