Regarding the radiator-to-hood ducting, I forgot that Vorshlag was able to accomplish this on their "Big Red" Mustang--you can probably pore through their blog and find the photos of how they laid everything out to clear stuff. It looked great but also very labor-intensive (read: expensive).
The good part about "labor intensive" is that it can often be done inexpensively by a DIY guy with a few tools and a little skill. Maybe not as fast or clean as we did it, but still achievable.
We actually did two different Mustangs. Our "Big Red" that was fully ducted on the front, and loosely ducted behind the radiator. It was a lot of work, but it really needed it for cooling efficiency and as part of the front downforce/drag-reduction package.
The other one was a silver Roush that was less of a track weapon, and more of a street car pushing it hard on track. We had to pay more attention to aesthetics, and had the extra heat exchangers to work around. There were no modifications in front of the radiator, and a loose duct behind it pushing air to the huge duct in a carbon hood.
The galleries have more detail than the build threads, though they don't have the commentary. I'll post links to the point in each gallery where we built the front ducting on each car.
The Silver Roush starts here, where we received the hood.
https://vorshlag.smugmug.com/Vorshlag-Test-Pilots/James-Meeker/i-BBT9ddZ
There is a small break, and then more photos showing us repositioning the underhood parts and building new tanks.
https://vorshlag.smugmug.com/Vorshlag-Test-Pilots/James-Meeker/i-8xVQF6Q
And here are some of the final photos.
Underhood showing the space we opened up at the front of the engine, to allow better airflow through the duct.
For the Red car, here is where we start moving things under the hood, and then build a new bumper beam to allow front duct space and to support the splitter. Then we build the front duct work and THEN we cut up the stock hood and build the super slide ducts in it.
https://vorshlag.smugmug.com/Projects/Vorshlag-2011-Mustang-GT-build/i-nKkkgQ2
Here's a good photo showing under the skin at a test day.
The brown thing in front of the radiator is a piece of Nomex honeycomb we used to protect the radiator during bug season. There were a couple events where we had to scrape off a couple inches of dragon flies off the radiator. We removed it when not needed.
A good shot showing how the tanks and intake were repositioned to make room for the hood ducts.
Neither of these projects were one-and-done. Both required some adjustments and changes to optimize them after the first iteration. Thankfully, small things, like different tanks that worked better, or fastener changes. And they allowed us to experiment and fine tune what we would do for future projects, like the V8 swapped BMW E46 or the '69 Camaro tube frame track weapon.