will definitely work for you, but it also includes a valve. You may be able to find a standard orifice at the hardware store. This one specifies an orifice opening of .052", with an output rating of 21,200 BTU.....which is a bit low for brewing IMO.
When you say "low pressure," do you know the specific pressure you are referring to? The reason I ask, there are several retailers that refer to 10 PSI as low pressure, which it is not. In this case they are usually comparing it to other items in their own product line that run at 20-30PSI. True "low pressure" LP's pressure is 11" Water Column (about 0.5 PSI). At that pressure you are going to have a hard time getting enough heat out of the BG12, especially if you are doing batches over 5 gallons.