Well... if you have spent the $$$ on the MSD ignition, just spend a litle bit more to get it set on the dyno. Advancing the timing too far can cause detonation, and WILL harm the motor. Besides that, getting it done on the dyno you can see where the gains/losses are to be had, and you can then make an educated choice to have it set to where you want it.

Just go dyno it!