Rust in floorpan on both sides of the seam

[pound41]

I posted a thread on this in paint and body but no one responded so I must be breaking new ground here. Anyway my driverside floor pan has heavy rust on both sides of the factory seam. The replacement pan goes above the original seam. Do I need to cut 2 pacthes and seam it back into the support bar like the factory or can I go over with one floor pan patch