Everyone wants to know how to cut-in a electrical device box. This is one of the many basic task an apprentice learns but a very important one. Unfortunately, all it takes is making one wrong cut and back charges start rolling in from the drywall contractor. It is basic but must be done correct first time. If you are D.I.Y. then you can fix the drywall patches yourself, right? This can get messy but can be done.
Tornado clips and jiffy clips, box supports are same thing, just different terminology. And if you are using metal or plastic cut-in it is your choice. For most applications purposes, commercial uses metal and residential use plastic. This is because of code issues and cost.
If I were to get in tight spot, I would use metal anywhere because it holds up better and gives a straighter look. But remember you have to ground a metal box with a ground screw and have grounding conductor available.
Metal gangable box can be used as one box or five put together by removing the sideplates. This is a nice little box to keep in stock.