When I was usign my open ended barrel, the bars were scrap angle iron, pipe, bar stock, anything iron/steel with some 'heft'. Figured to replace them every year or two. Barrel was usually good for about 3 years.
An open ended barrel with grid under will burn better than any other type of barrel modification or open sided container. The barrel, once lit off, has a draft that would suck your hat off.
Harry K