The correct waste ratio for any RO system, regardless of vendor or manufacturer depends on your exact unique water conditions. BRS is completely out in left field advertising their 150 GPD as a water saver. There is no such thing with a dual membrane system period! You are taking the concentrated waste from one membrane and sending it into the second membrane then trying to further reduce the waste ratio and further concentrating the waste into a sludge. How long do you think your membranes will last? If it were really that simple every vendor, most of whom have been around much much longer than BRS, would have been selling these decades ago.
The critical things to consider when buying a system that you may or may not want to attempt reducing the waste from the industry standard reccomendation of 4:1 waste to good is your tap waters calcium carbonate hardness, tap TDS, incoming pressure and incoming temperature. If you have hard water forget about reducing the waste. If you have softened water but still have high TDS you might be able to reduce it a little. If you have very soft water and much lower than normal TDS then you can probably get away with reduced waste and still get decent membrane life.
All membranes must be flushed, there is no way around it. Flushing is acheived via the waste stream which carries the concentrated brine away. Its not flush kits and its certainly not reducing the waste flow which allows TDS to solidify on the membrane and no amount of flushing in the world will ever remove it at that point and the membrane is now on its way to failure.