What 3 or 4 axis motion control sliders are often used? I own a classic Alexa, which weights over 18 lbs with a lens attached, and I am planning to hand a really robust electric slider/dolly. I know the Kessler CineDrive and Cineshooter can support up 25 lbs, but is there other option on the market? I found so many professional sliders are limited up to 15 lbs, such as the eMotimo ST4. Beside deciding which one to get, I also want to know what motion control systems people on high production levels use. Do those products take the form of a slider even?