What is the best thickness for depron foam (as rc model structure)?

[Commander Fox]

Good afternoon RPF Community,

I've a question. Recently a friend of mine told me that to build RC Airplanes models, depron foam is the right material. But he didn't tell me the exact thickness.
Now I'm working on the "HWSS Challenger" Project, an experimental RC UFO model designed by me. But, in order to do it, I need to know the best depron foam thickness. Has anybody ever built a RC Airplane using depron foam? If so, could you tell me what is the best thickness to choose?

Quick extra question: if in the RPF Community there is any Italian user, could you tell me what is the "depron foam" Italian name, please? I'm not finding it on the web, not even on Wikipedia.

 

[MonsieurTox]

I always used 3 mm and 6 mm depron, it's up to you to figure what's best depending on the part and of the stress this part will take.

 

[Commander Fox]

I always used 3 mm and 6 mm depron, it's up to you to figure what's best depending on the part and of the stress this part will take.

Well, the UFO will be a big RC Quadricopter inside a depron foam structure. Together with the Quadricopter there will be some extra electronic components such as the lights and the batteries and some (possible) extra mechanisms, but nothing else.

Small extra question: what's the size of the biggest RC Quadricopter that can be bought?