lil bull

Well it looks like I am going to replace the whole firewall on my 65 coupe instead of patch panels, it is just to far gone to screw with it. The question I have is for those who have done this, is there any secrets to it or anything that has to be perfect on the alignment part? Other than what might seem obvious that is. All 4 inner panels in the engine bay are out. I thought about bolting them to the shock tower temporarily as a guide. I also have to replace the whole cowl top and both sides. Just looking for some advice before I tear the old one out and get started. Thanks