My slider changes out single cartridges.
http://www.teleskop-express.de/shop/...w-profile.html (this is 2", I use the 1.25" version)
In theory you need 2 drawers (you can buy extras), one in use and the other to load out (so your filter swaps are rapid). Probably better is to get 3-4 of them and have your filter run setup for the night.
These work great if you're not trying to automate, and are happy to run sequences rather than loops, e.g. 10 x L subs, 10 x R, 10 x G, 10 x B - if they were 5 min subs you'd be swapping out every hour or so, which is a good time to re-focus! That's my MO, anyway.