"...a good method to determine your bullet seating depth. i have heard so many of them but need one that works! "
You hear so many ways to determine the MAX OAL because there are so many ways to do it and they all work fine if done properly. But, nothing works well if it's done improperly.
The Hornady/Stoney Point device is as good as any, it's fairly easy to use and very versatile. You have to use it along with a precison caliper but every reloader should have one of those anyway.