Shooter Grrl,
I worked with the weakhand method and finally gave it up due to physical and visual limitations. After experimenting with a number of methods, I found that something similar to the one described by Jim Norman to be best for me. Instead of rolling it upside down ,though, I leave it on its side and slide the shotgun rearward, as my right hand moves to the side-saddle. This position gives me a solid base and a clear view of the loading gate, side-saddle and the stage. No stress at all on the shoulder, arms or neck. With just a little practice, you'll rarely fumble a reload. Another benefit is that the muzzle stays pointed at the targets and at eye level. As the last round is loaded, simply push the muzzle toward the target as you roll the shotgun into the shoulder and squeeze the trigger. As Jim mentioned, your strong hand has full access to the shells whether you're using a side-saddle, wrist band or Choate speed feed on the belt. Nothing to get in the way. This is the fastest method that I've been able to master.
It's the "Cats Meow"