IF, and I say IF you can get ALL Of the old cork off the pan and the block, installing the one piece gasket would be my preference. My son does those all the time with only dropping the pan an inch or so. Trick is getting the surfaces clean and dry.
Any chance the rear main is leaking and not the pan? Very common on the 2 piece rear main. My new 350 just started dripping from the main. Pan gasket is dry as a bone. Not planning on changing it any time soon. It drips a few at night and while i'm driving but i'm too old to care and its too hot to do anyway LOL.