HAWAKEYE,
Many new regulators need a break-in period to "settle in" and become consistent. Best to have a chronograph and shoot over the chronograph until consistency is reached. The chronograph will tell you when your regulator and your new gun has broken in. Without a chronograph, you'll just be guessing. Without a chronograph, the only help you'll have is to watch your groups become tighter and tighter. Your groups will be determined by the consistency of the regulator, the seasoning of the barrel, and the sealing of your seals, and your improving ability to hold the gun steady with practice. Sorry, I don't have a general rule of thumb to estimate how many shots it takes for the regulator to settle in. You have to determine that yourself. Get a chronograph.
BeemanR7