That's what I did. Movie: The Movie Starscream mold is the easiest to hang. The thumb tack rests right where his thighs meet in plane mode. You can even tilt the plane to give it a dynamic flight look and it will stay in that position! Voyager Megatron's have a hole where the waist locks into the torso, so that's where the thumb tack goes there. Blackout uses 2 tacks that fit in between each arm and his torso. Incinerator uses 1 that fits in the front landing gear bay. The cyclops clones each use 1 that fits in between the feet and hooks on the top one. Thrust's fits in his landing gear bay. Unicron Trilogy: Armada Starscream mold works easiest. Requires 2 tacks per jet that lock in behind his elbows. Scorponok locks in with 2 each using the parallel bars on his claws that move. The tacks fit right in between them, spacing affects how far the claws pull away from the torso. Cyclonus is a pain in the ass. Using 2 each, it's a bit risky, you can slide them into his shin gun holes. It doesn't hook, because of the angle of his foot, but the leverage of the rest of his body does hold him in place. Buzzsaw remold was the worst. He's using 5 tacks. 2 the same way was Cyclonus, but with 2 right above his toes and 1 underneath the trigger so he can't lean back and pull away from the wall. Thrust uses 1 each, slides in between one of his legs and his center neck flap. Could use 2 to ensure a straight fit, but 1 is close enough. Cybertron Jetfire mold. On his legs, there are a set of ridges. Using those and 3 tacks, I mounted 2 next to each other on the bottom ridges for balance and 1 on the top ridge to lock him in. Cybertron Thundercracker uses 3 each. 2 for balance on the bottom using 1 on each side of his arm, then 1 locks on top of the tabs on the bottom of the cockpit snugly. Energon Starscream very similar to Cybertron Thundercracker. I've had my figures this way for a week, and none have fallen. I've experimented with Cybertron Wing Sabre and Movie 1 Leader Megatron, but neither have good spots on them to hang with. Perhaps I'll get some ceiling hooks and string for them next? Oh yeah, I do notice the missiles missing on Thundercracker and G1 Starscream on the movie side. They were in a tote full of Minicons before I got this idea, so I gotta empty the tote and go fishing for them.