Bulkhead F-402 Dilemma

The previous builder claimed to have built all of the bulkheads, so I wondered why F-402 was still in four pieces. It turns out that F-402 intersects with two ribs (F-413) which attach to the F-401 & F-404 Firewalls.

My biggest problem was that I could not find brackets F-442, which are  attachment points that fit on either side of F-413 ribbing. Eventually the engine mount connects to these F-442 brackets through the firewall.

Furthermore, I could not locate an aluminum angle piece that connects the two ribs via F-442L & R. Are these angles, when not specified by part number always fabricated by the builder?

Eventually I found brackets F-442, but it appears that I have made my first mistake, which corresponded to the first holes I drilled in them and the angle piece between them. I did not allow for the additional angles which run along the top of F-413. This added 1/4" to the called out dimension of 7 1/2"

The plans are very inadequate in constructing this rib assembly. You have to search through three or four drawings to figure it out. I also found two 3/4 X 3/4 X .125 aluminum angles that run the length of both F-413 ribs. Unfortunately one of them is about 7 1/2" too short now as I used part of it to create the angle piece that connects the assembly together.

Although this assembly could have been made much later, I hope it will be useful in verifying the distance between F-401 & F-404. Although I need to complete it before I can place it in the fuselage. Here is a side view of the same assembly.

Probably going to need some help from Van's on this one. I cannot interpret the drawings.

I have the following questions  on this assembly:

1. Are the 3/4 X 3/4 X .125 angles which run along the top of F-413's precut or do I cut them from the stock angle material on hand? How much extra is in a typical kit?
2. Is there any better detail about how the angles attach to F-413 ribs, F-442 brackets, and F-443 brackets? (I am also missing spacers called for in the plans as F-444)
3. Do you attach the vertical angles on the F-401 Firewall first to accomodate this assembly?
4. Am I getting way ahead of myself? Should I be focusing on longerons, bulkheads, etc before tackliing this?

Any help would be appreciated.