We just removed a coat closet in our entrance. I now have 8 step to the upstairs with a wall on one side and 4 open steps (less than 36" high) and a wall on the other. I like the open look and would like to leave it that way and place a handrail on the full wall. The rail would be about 7 ft. I want a metal rail but am disappointed with the high cost of the rails I've seen. How big in diameter does a rail have to be? Could I use a shower rod, curtain rod as rail or do you have a suggestion?