You can get precise results by using a simple circle cutting attachment consisting of a torch holding bracket a rod and a pivot. In future if you require smaller or larger holes you can adjust the pivot and cut accordingly.
What is the thickness of the sheet. What is the product and service conditions i.e whether load bearing , pressure application etc . This will determine the welding process to be used after taking into account aesthetic looks.
For a 0.040 SS sheet pulse may not even be required. A steady hand , short arc gap and .040 tungsten will do the needfull. The power source whether its miller or lincoln will not make a difference.
