Man, that first post hits home—I messed around with a similar setup on an arm prototype a while back and kept running into the same issues with sizing. In my experience, shorter strokes around 1-4 inches (roughly 25-100mm) tend to give the cleanest motion in tight joint spaces because you avoid weird leverage angles or extra linkage hassle. Force-wise, I've found 20-60 lbs (about 90-270N) hits a sweet spot for most lightweight arms or legs—enough to handle a couple kilos payload without straining, but not so much that it jerks or overheats on repeated cycles. Anything higher just feels unnecessary unless you're lifting serious weight. Lately I've been eyeing automation projects https://www.progressiveautomations.com/en-eu/pages/standard-linear-actuators from places like Progressive Automations since they come in those compact sizes and seem reliable for hobby-level stuff without going overboard. What about you, anyone else settle on specific numbers that just clicked?