Ok, To begin with due to a hard drive crash I have lost most of my early pictures. However, I will try to have photos that show what I am talking about for the different sections. Since I am widening my fuselage by 4 inches I had to widen all the pieces for chapter 4 by that amount. Through trial and error I found different pieces had to be expanded in different places.
Step1 : Front Seatback
This was a standard piece, add 4 inches horizontally and cut. I waited until later to put the 45 degree cuts on the top and bottom since (being a noob) I wasn't sure which way they would go. I also waited to cut most of the holes around the sides of this. Hint, if you wait to do this until after assembly you make a bunch more work for yourself.
Step2 : Forward Bulkheads
This consists of the F22 and F28 bulkheads, along with the F22 doubler. Here's an overhead view of them when I was working on chapter 13. in the overall picture these are the items around where your canard mount to
Step 3 : Instrument Panel
This one gave me some trouble. I had sat in a standard cozy at this point and was not happy with where my knees hit on the panel. I am 6'2 and my knees were coming right up in the bottom of this bulkhead. So I made a few decisions. First off I pushed the seatback I made in step 1 back 2 inches. In doing so I upset the placement of the seats in chapter 24 how the bottom of the seat meshes up with the smaller opening in the instrument panel. So I did away with those too, just one big opening for the feet and legs. This picture was taken while I was working on chapter 16, but it illustrates what I did. I lost a bit of panel space, but I'm hopeful I can work around that.
Step 4 : Landing Gear Bulkheads
These were pieces that I eventually had to rework. In widening my fuselage I mistakenly just added 4 inches to the middle. However that throws off where the hard point is located for the main gear to be mounted to. Also by doing that I unintentionally made my naca scoop 4 inches wider. very ungood. you can see in this picture where I had to rework the naca scoop to the proper size.
Step 5 : Firewall
The only problem I ran into here was the naca scoop being too large. When I went to install the main landing gear in chapter 9 I could not put a cover over it because of the scoop being too large. Resize, learn a lesson and move forward.