Shannon, the one piece looks pretty good in the cars. I opted to go with the original style. I have only done 2. They are a pain, but if you have a day, you could do it. Its just a lot of pulling and gluing to get the wrinkles out. If you do go with the one piece, the galvonized pieces that you mention are only held on by clips. A pair of diagonal pliers will make piping those clips out a snap. Dobt throw those strips away. They are not easy to find. Someone o, this site I'm sure would buy them from you.
My car looks a lot like yours, mine is orange with white stripes, and white seats, and door panels. My carpet is black, package tray is black and my headliner is black. I think the headliner should stay black. White would be very overpowering. Just my thoughts.
1969 x-77 Z/28 orange/ white stripes, named by my daughter "Clementine ", M-22 close ratio, 4:10 12 bolt, CE 302. Hugger orange with white stripes. White standard interior. Restoration complete May 2018