Need help on firewall hole for C/S Prop Cable

After 2085 hours of flying with behind a metal Sensenich FP prop on our RV-6A, I'm finally upgrading to a Hartzell C/S prop with a Woodward Governor.

I do not know where to drill a hole in the firewall for the prop cable to go through then line up with the Woodward mounting bracket.

If anyone out there has this information (some measurements for where to drill the hole), I would appreciate some guidance here. Thanks so much, Rosie

Governor hole

It needs to be just above middle the X brace on the left side.
measure down 8" and in board 7 1/2" from rows of rivits top and side.
Jay