From DO-IT's catalogue
Insert Collar Cavities Hook Style Sizes
#12 Crane Swivel Barb 5 570
575
1/32 1/16 1/8 1/4 3/8
Split Ring Size 0 0 0 0 0
Blade Size 00 00 0 1 1
Hook Size 6 4 1/0 1/0 2/0

You can adjust blade size and as much as I have tried, the size 0 split ring is the best but is a real PITA to use. Butt rings can be used but are not as durable as the split ring