The effect of seating to the lands is fairly complicated, and sometimes the effect on accuracy is overrated. The support given to the shank of the bullet by the case mouth AS IT ENGAGES THE LANDS is critical. If you are only 1/8th inch into the lands and the base of the bullet is released by the neck, the bullet will yaw in the throat anyway. Shallow seating can also cause large variations in starting pressure. You may be better off seating to the base of the neck and making sure you have full uniform neck grip and/or crimp while using cases fireformed to your chamber. This, combined with a mandrel type neck sizer may give you better groups than seating way out to touch the lands.