I built a four-position stand and a four-way drag compatible launch controller with LED indicators; there is a page on the system here:
https://rocketry.newcenturycomputers.net/launchsystem.html
with photos, but no plans per se. I didn't use plans to build it, so I don't have plans to show you. (Well, I did create schematics for the launch controller, and they are on the page).
Note that the page is in reverse date order, blog-style, so if you want to follow the whole build you have to start at the bottom and work up.