Larry,
Look at my paws on that 20 gauge Darne. I don't have tiny hands, but, they aren't catchers mitts, either. If you ever have the chance to handle a 28 gauge Darne R action, I think you will realize, that it is do-able. Yes, you would have had to order a fitted gun, probably a 20 or a 28, and it would have been better to show up in town to let the builders see what they had to work with. Yes, you would have to want to make it work.
But, it could be done.
Maybe not off the used gun rack at Cabelas, with a 12. But, where there is a will, there is a way. Your trigger finger has to be in the neighborhood of where the safety is anyway, conventional gun, or Darne. And, you could still use the opening lever as a safety, so your trigger finger doesn't have to do anything except get to and pull the trigger. The opening lever IS a tang safety, Larry, a big, obvious one, right where you think they all should be.
Totally doable. Or, it was, anyway.
Best,
Ted