I recently bought a low-cost XT30 balance board that I would share here given it does the job I would expect at a low price: the XT30 1S-3S Plug Parallel Charging Board For IMAX B6 Charger. Although advertised as working with the Imax B6 charger, it will work with any 1-3s capable lipo balance charger that uses banana plugs.
The balance board can be used with 1,2,3,4 or 6 batteries with a XT30 connector and standard balance plugs for 1-3s batteries which will cover most micro builds. Each XT30 discharge lead is protected by a fuse if there is a large voltage differential on connection.
I also purchased this lead that I will modify to with an XT30 male plug from this set for input so that I can also use this balance board for my batteries with JST discharge plugs.
Below is a list of key rules for balance charging but certainly no exhaustive in terms of instructions: