should be 9 1/4" back from the driveshaft and down 6 3/8" from the inside top of the tunnel. referencing the driveshaft, your using the flat plane on the shaft measuring back from it.
just having the front mount wont work, so the rest of the needed measures are center to center from your new front hole: 13 3/8" to the center mount and from there c2c 15 1/2". down 5 3/16" and 7 5/8" respectfully. yamaha included provisional mount holes for center and rear. center being 5/8" lower and rear being 1 1/8" lower.
essentially your moving the three mount points somewhere in the neighborhood of 4 3/16, 4 3/16, and 5 3/16.