A few things to add/clarify...
• You can move your BTC after the snapshot block is taken.
• You do not need to relink your Bitcoin addresse(s) every month.
• When you send Byteballs, if you send less than your full balance, you will also probably create a Byteball change address. For the Blackbyte distribution you will want to link this address to a BTC address, even if the BTC address is empty, or move your Byteballs back so that you will get Blackbytes for them.
Enjoy and good luck!