The tail light gaskets fit well. I didn't look too hard, but they don't look like they have the splits like the ones I removed.
I made new rubber washers with punches, 1/32" thick 40A durometer rubber sheet.
It's not the prettiest repair, but it should keep the water out.
We had some good rain here after I installed the tail lights. It appears that they are not leaking any more. One Wed the quarter panel vents will be here. Before I install them I'll give the tail lights a good soaking to make sure the leaks were fixes.