I have a simplicity riding mower with a briggs and straton 15hp ohv vanguard engine model 280777 type 0612 A1 need to know how far to set the pick up coil from the flywheel

For the home mechanic you can use a normal business card between the coil and the flywheel, tighten it down and then rotate the flywheel and remove the card. It should be fine.