The very last thing to do is to seal the overshot card in place so it doesn’t move during recoil or from just being carried. Some of my wife fingernail polish she no longer likes is the best stuff I’ve found.
Now, you are ready to hit the woods with your vintage shotgun!!
The only thing that I do differently for using in my 1893/1897 Winchester and 1898 Marlin is put a light roll crimp on the end of the brass to aid in feeding from the magazine. This is not necessary nor desired on rounds for single or double guns because it simply makes the brass wear out faster. Also, the crimp is not shot out when the shell is fired. The only way to get the crimp back out is to take something tapered, such as a ratchet that is tapered to the right size and use it to swage the crimp back out. If you do have the crimp them- anneal them first as it will make them last much longer.