looking for any information about installing quarter panel skins on a 68 2dr. full quarters are not available. would you recommend lapping them or butt-welding? any experience or help is appreciated

On the 70 I did in 1992 I overlapped the new quarter by 2 inches. I trimmed the new quarter back so that the seam would end up in a nice flat area with plenty of space to spread the filler over the seam. At the door jam I butt welded it. The longboard sander is a must when doing the filler on a seam this long. And you'll need a lot of filler. It looked very nice and straight when I was done. I welded it every inch or so and spread the welds out so they could cool.

When ever you make a cut on panels that will end up on top of an overlap weld use a skill saw with a metal cuting blade to get a nice clean cut. The cut on the bottom can be done with an air chisel as long as it is a couple inches away from the seam.