The gas tank is inclined 15.75 degrees.
If you want the (pretty) exact position of either the holes in the tank or the frame, I have raw measurements and DXF files, here:
https://tinyurl.com/exocet-gas-measurements18
I'm currently 3D printing some mocked up mounts to see if everything fits as expected. If so, I'll put together some CAD files to send to a waterjet/CNC brake. To give you some idea of alignment, gold is the frame and blue is the gas tank (turned backward, fuel neck in NORTHEAST corner of this picture).
