Mainly on the 20gauge triple I use the lead NSI 31gram #0 and in the 12gauge I use the NSI 32Gram #2. I use this for rabbits, hares and foxes. The reason is because I film everything, If I use a heavier cartridge then the camera is pointing at the sky after the shot. I also noticed that I can deliver a faster second or even third shot with the lower weight cartridges. Years ago I would have used 42gram BB loads in the foxes but after years of using the lower weight cartridges accuracy is more important than payload. Also dropping from 42gram BB to 31gram #0 has exactly the same pellet count and the #0 shot is 3.9mm versus 4.23mm in the BB but both provide enough penetration.

Here's my comparison

https://youtu.be/WHZdEmt-WFA