My wife is right handed, but left eye dominant, thus, she shoots lefty.
AFter kicking my behind continuously, i finally got her a Browning 525 O/U lefty
Now it's even worse how bad she beats me. But I gotta admit, it felt TOTALLY wrong when I picked it up, so I guess I know what she was going thru. (palm swell wrong side, etc)
She likes a 12 3/4 length of pull

, so we had it shortened by a gunfitter and he put some weight back in the stock to balance it. It slides right up for her.
Spend the $200 bucks and have it fitted correctly, you won't believe the difference.
You can get left handed stocks from Cole's for Beretta 391's
But any good gunfitter should be able to bend it and get the LOP correct, along with the angle at the shoulder.
Most women have long necks and need a higher comb also.