Mustang,
My first gut reaction is that if you are designing this install, Are you comfortable with it? Do you believe in the install? If not, if the Sh** hits the fan, you are going to be the first one that hits the hot seat in court. You designed it and if it was inferior, you might be the one who gets hung for it. Even if I was the AHJ on the job, if you are an engineer, the you would be qualified to design something. I would have to acceot your qualifications as an engineer for the design. If you are not an engineer, then I would get someone who is, so that his lic. is on the line. Why put out your neck if you don't have to. The customer will have to pay the bill for the engineer one way or the other.
