A Body Floor pan question

Have a 1970 Duster and need to address the front floor pan on driver and passenger side. Car is back halved so only need front 20 inches from the front seam back. Or..... I can patch. From the seam back would be easier I know, but much more money because Id have to buy front and back. Seems my options are limited because I cant seem to find Front half patches to the firewall seam. Or am I not looking in the right places??? Thanks in advance for any help or advice!!!