Tests have shown that the base of the bullet is far more important in flight than is the nose.
Dan Newberry's system is a good one, often recommended by UncleNick.
You can use a variation of the Newberry technique to establish your preferred OAL also. Simply use Trail Boss powder with a fixed charge and vary the OAL rather than the powder charge. Once you have established the OAL that particular bullet likes, continue on with Newberry's method for the powder charge.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.