Uhh, he already figured it out, his map in SS64 is living, breathing proof of it.
Control sectors DO NOT require 3 sides. If you could make a sector with two sides, it would still work fine. Same with 4. In fact, I could even make a Floor over Floor WITHOUT a control sector.
Also, know which linedef type you need exactlty before you start spouting off numbers.
And please, you just missed the whole concept of linedef executors.