I would not use channel to start with, I think it looks a little to "home made", the real thing looks more professional.
Go ahead and get the right strips from http://www.mar-k.com/

If you want them to be black get the unpolished stainless strips and have them powder coated. Then you don't have to worry about rust. If they get ugly looking you can always have them re coated.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-