Theworm

I've seen plenty of dead posts relating to stitch welding and fabrication. Though none of them actually assisted me in answering the questions I had. I guess my first question is, how do engineers/fabricators know where to add dimpled piece (i.e. above the A pillars between a roll cage) and to strengthen the car. How can you tell where you need to actually need to stiff the body? Secondly, I've seen debates on inch stitch welding and spot welding. This is more opinion unless proven by some legit documentation that one is better than the other. Am I correct in assuming this is more preference?

Please no flaming, this is a debate/conversation.