How to make Rotisserie Sirloin Tip Roast: 1  Coat the sirloin tip roast moderately with onion powder and garlic powder and salt. 2  After 24 hours, remove from refrigerator and bring the meat to room temperature. 3  Place in rotisserie for 20 minutes per round.ow to make Rotisserie Sirloin Tip Roast: 1  Coat the sirloin tip roast moderately with onion powder and garlic powder and salt. 2  Refrigerate the mixture for 24 hours.