The one I found would not fit was the engine from the 25 T into the forty coupe or sedan. It looks like it should but there is interference with black and frame.
I've done the 40 ford with the hemi but it needs the firewall modified for the fan belt and fan to fit. Also the pontaic from the 36 fits into the 32 ford but the firewall needs to be modified and a little adjustment to trans.
If you are using pearl powders you mix them in clear not the solid color.
As far as the cameo colors I would you the clear with flake and leave them glossy. I can't see that you will get the metalflake look without it.
Chris I think at this point you are going to have to use what you have. Nobody can dispute what you do if there isn't more to go on. Have you tried to see if there are other cars of that vintage that might help. Also you know who did the chassis you might be able to use to help fill in some of the blanks