That's pretty good advice, too. Fit of the stock, and little that can be done with the original wood to correct it, is a problem with a Darne.
Most folks who get into, and then get out of them, have issues with the way their gun fits them.
You can use the opening lever as a safety also. If it is up and out of the cutout in the sliding breech, the gun won't fire. The lever will politely remain open, against your thumb, under a little spring tension, until you snap it closed. Also, the safety lever can be flipped to the other side of the breech block on an R model if that works better for you.
There was a time when a pretty nice old Darne was $500 at a gun show. Those days are gone, from what I've seen.
Best,
Ted