Oval router jig?

Hello all, currently building some mid/hi cabs and am going to use Adam Hall SM707 adjustable top hats but have no idea how to go about making a router jig for them as they are oval.. I have made many jigs in the past but always for round/square or rectangles which are pretty easy. Any clever suggestions gratefully received!

You could draw it at the appropriate size allowing for the size difference in the guide. cut it of a piece of 6mm. From there you can transfer it to something that will suit your router setup in terms of thickness, i.e. how far down does your guide protrude through the base of the Router. Once having done this, you're away.

Thanks Tony, that's what I thought. What concerns me is that the drawing and cutting would have to be done freehand. Any errors will show up every time then.. Just have to be very carefull I suppose!

When I made something similar I just used the top hat as a template. Laid it on a board, drew around it and carefully cut it out with a scroll saw. Do as mentioned with the extra bit for the router, because when I did it I forgot to take that into account so I had to go back and trim it by hand.