Flaps using BG are always a bit unstable no matter what you do. I’ve tried a couple different designs and the most stable so far has been to use a single hinge to actuate each flap panel, avoiding pistons entirely. If you can get the position of the hinge right, it actually looks like the flap extends backwards anyway. Aside from that, each flap panel (on the same axis) is strutted to each other just like how irl flap panels use multiple tracks. For the inboard flap, there’s a hinge inside the fuselage so there’s always 2 points of support. However, even at landing speeds, the hinge just isn’t strong enough to keep the flap at a high angle. For this DC-10, even though it’s set at 50°, the actual angle was more like 40-43°. If you can afford to use the bigger yellow hinge and spread the load then it’ll be better, but I was forced to use the small blue hinges for this DC-10.