Thanks Gamera! I kicked off cutting plastic last night:

I think a sheet of 0.020" got into my packet of 0.030".
I was wondering why the bottom plate was so easy to form. Anyway, too late, gonna keep going!
I'll just use 0.020" to plate the bottom when it comes to detailing. I now have to make sure I can cut those "happy" windows with the arched tops in a neat, evenly spaced manner.