I have a 640 Pro. I can load RN bullets faster with moon clips, anything else speedloaders are faster for me. All fired cases eject at the same time. INHO they are better for short stubby rounds like the 45 ACP revolvers then the long skinny 357. They are nice for have lots of rounds ready to go for training or range sessions.
You can send the gun to TKS customs.
My rifle and pistol are tools, I am the weapon.