I would vote for steel siding also,
I have it on my inside walls and ceiling, it has been there for 12 years and I could not be happier. It gets a little dusty once in a while so move the equipment out and spray it down with a hose. I would think that would be hard to do with drywall without damage.
If you place cross bracing between the studs you can mount just about anything you want on the walls, It is lighter in weight than 1/2 in drywall, it is already painted and usually carries a 20-25 year guarantee on the paint, if you use a light color it is very easy to get good lighting, you can blow insulation on top of it or insulate it same as drywall, in my opinion it is a whole lot faster and easier to install than drywall, and it takes no taping or painting after it is hung, once installed, it is done.
I would still use the lights you have, just hang them with lightweight chain.
I am wondering why Haugy says not to install it?
Jim