Nicos,
Unfortunately for the 350EW model, there was never an illustrated version of the spares list. Or none that I have ever come across in the last thirty years. They did one for the 600EW, but not a lot transfers over to the smaller model.
As for the frame, you will have to ask fellow 350EW owners for specific dimensions. I do have a '27 350EW that is in a practically bare-frame state right now (though in storage), so could probably pull some dimensions given time.
-Doug
[split topic to separate post. 20Jul16 Doug]