Unfortunately a trammel will not work for this application, I can mark a perfect ellipse with the trammel but I could not use it to run moulding as the major and minor axis have an extreme offset. The major axis is over 180cm and the minor axis is about 19cm. Because the trammel uses pivot points sliding through a preset tracks and not true radius running the knife noticeably would drag through the run skewed once it is off the major and minor axis center points. I attached a cad screenshot to visually explain it, not sure if I am explaining it good enough. In the screenshot you can see the three colored points the knife would run using a trammel. The yellow indicates major axis center pint where the moulding is 107.95mm wide, at the cyan colored line point the knife is running skewed and the moulding is now @ about 101.6mm, at the green colored line point the moulding is now @ about 92mm, as you continue through the run the knife would correct itself When parallel to the major axis. The white lines are the radius angles the knife should be at.
Cheers