Warspite, I just can talk about my experience (which will be oppositional to others), but I don`t fancy plasticard. I have found out, that i.e. superstructure made in 0,2mm brass or 0,3mm aluminium plate is more stable and easier to be made. You can solder it and you don`t have thermical problems when on the pond on a hot sunny day. No matter which glue used, after two or three years of service the edges start to crackle, sides became weak and being deformed by the temperature.
Then I made some tests and a 0,3mm brassplate has the same weight as a 1,0mm plasticard. 0,3mm sounds very small, but good enough for smaller superstructures. For bigger boats, where you don`t have to care too much about the topweight and you need to make bigger superstructures 0,5mm or 0,7mm will do a perfect and stable job anyway.
Hope this was out of any help,
Jörg