When the RCM plan was first published a .60 was the big engine. Now there are all kinds of choices so don't worry about the weight. Larger engines can even be used for balance purposes. SO when you get that far then you can decide what you need for an engine. Foam cutting is not rocket science. Just get a 12 volt battery, about 3 feet of ni-chrome wire make a bow of some kind to keep it tight, do a little research and practice a little. It won't be too hard. Good luck