Ahh, I got that wrong, apparently it's 5".
That's exactly what I was planning and was the picture that I used to plan my build. I did get my numbers wrong, thanks for the beta.
So I need a 5" collar for the air filter, and then a 6" to 5" reducer for the top of the SDD to HF inlet and a 5" to 4" reducer as well for the inlet of the SDD.