In my opinion, there's no wrong place to start with seating depth as long as its effect on pressure is taken into consideration for safety's sake. That being said, you have to be willing to play with it some. I'd recommend increments of about 0.020" to a depth of up to about 0.150" off the lands or more to start, then fine tune based on what you see. I used to be very stubborn about finding seating depths in the 0.015" to 0.035" range, and I wasted a lot of components as a result.
