You need to know the inititial, total, and how much advance the cannister pulls in to get it dialed in. When you bump the initial you need to shorten the slots in the advance plate to limit the total advance. Spring kits only change the speed at which the advance comes in not the total. Then go to the vacuum advance can. You can get them in different Hg. ratings for different distributors or adjustable ones depending on what you have. You don't always hear detonation at higher rpm but it can kill some bearings in short order.