One good size cabbage makes about 2kg of chopped cabbage. 3kg of chopped cabbage is a bit too much for the crock, so stick with one big cabbage.
Use the finest chopping blade on the blender.
Use the smaller shoot & spacer to get closer to the blade.
Full the shoot, full speed, squash down for best results.
Wearing gloves is definitely much better.
Stock pot works well for mixing.
One tablespoon of salt per kg of cabbage. Usually this will be 1.5kg cabbage, so 1½ tablespoon salt.
Brine: Dissolve ½ tablespoon (1.5 teaspoons) of salt into 500ml of water.
3 weeks is more than enough for fermentation.