Here are the instructions for the JDS9860AA according to "Technical Information - Dual Fuel Slide-In Range" document that refers to JDS9860AA* and JDS8850AA*. The document makes it sound like no new orifices are required.
Orifice Conversion: LP Gas to Natural Gas
1. Screw the burner orifice hood away from the pins.
NOTE: On units using Eaton Oven Safety Valve, screw
the valve orifice hood away from the pins,
approximately 1 ½ to 2 turns.
2. Adjust burner air shutter to the widest opening that
will not cause the flame to lift or blow off the burner
when cold (adjust with pot in place).
My question is: how and where do you adjust the "burner air shutter"? The document doesn't make it clear. Thanks!