I personally would not make the door skins removable, I have never seen a car these days with removable composite skins. I would make sure there is plenty of access from the inside. The poor fitting panel need to be filled with marglass, you will have to extend the marglass a long ways to make it look good. This is a lot of weight. You may want to get is looking good with clay, and splash it, and make a new planel. My 2 cents.