It's looking very good so far I must say

I've had some good results from using slightly overvolted servos in front hinge flippers at antweight level - you've seen Jigsaw before and the mechanism on that works quite well despite having no real design thought at all going into it, although I'd advise beefing up all parts of the linkage including attachment points and hinges because if you do design it well and optimise it for maximum flip, there's a good chance the mechanism might have quite a kick in it towards the end of its travel or even lock up. Unless you model the lengths beforehand in CAD or card (which I anticipate you will being a better designer than me, heh) trial and error is the key to getting it right, and I had a fair bit of error :P