AFAIK that burner can be run on high pressure propane, low pressure propane, or NG by using the corresponding orifice. How cheap/easy it is to automate low pressure vs high pressure depends on how safe you want your burners to be. If you want the gas to shut off if the pilot goes out, low pressure is cheaper/easier to automate. For each burner you'd need a standing pilot furnace valve, a pilot, and a thermocouple. To do the same with high pressure requires each burner to have 2 solenoid valves, a pliot, and an ignition module, which is a bit more costly than the low pressure set-up. If you're not concerned about the safety aspect, you can use either high or low pressure with a simple solenoid valve and a pilot.
Keep in mind that it's unlikely you'd ever have all three burners going full blast at once, so the regulator doesn't need to supply the combined max output of all three burners. My 200,000 btu regulator works fine for me, but my system is a HERMS with only two burners, one for the HLT and one for the BK, and they're rarely both firing at the same time.
I'm not sure what your plans are, but most systems only automate the HLT and MLT burners, and leave the BK burner manual since it only needs to be lit once for a brew session. Skipping the PID, valves, pilot. etc for automating the BK burner could save you some money.