If you had BRM problems in the past and your initial deposit is going to be $600, consider that deposit your "zero". If you drop below $600 at the end of a given session, even if it is just 1bb, move down to 5NL until you have your zero + 2 buy-ins and start over. Every 4 or 5 buyins move your "zero" up and repeat.

Although this exercise is completely unnecessary with such a large BR for the stakes youre looking to play, it will help with your BRM discipline if you can stick to it. Once you have confidence that BRM is no longer an issue, you can move to standard BRM practices.