I have a GSN3318 propane grill from perfect flame. It has 4 main burners, a side burner and a back burner for the rotisserie. I want to convert this to natural gas but I am having problems getting correct orifice sizing. Perfect flame makes a natural gas version identical to what I have and when I contact the company to get replacement parts all they could tell me is the parts are out of stock. Look for direction on what drill size I need and where to get replacement orifice blanks in the event I screw up, not that I will. Thanks