Measure, remeasure, then measure again
Cut out the shaded sections.......
4 inches cut out on top and bottom, with a line connecting the two sections (front and back). Imagine the rear part of the tank just sliding forward. This keeps the gas cap and the bend of the top of the tank the same.
A few tack welds to hold it together
Perfect fit. Check out the pockets in the tank around the intake rockers. No interference. I hope the left tank fits this nice. I just finished cleaning it out and I think John's coming up on Sunday to go another round.