It's been done over and over. You could go that route, but at the end you're left with the decision to try, and if it doesn't work, you start all over again, or just buy the ready made, proven solution.
Thats where I have landed. I was considering the spectra universal kit x 2. That's $120 with ducting. I want something that looks a bit more refined under the hood, and so it looks like I may wait for NW or just do the V8 Cover now until the NW single comes up used.