I built the fire basket (13.5" diameter) with 5 5/8" tall (42.5" long) 9 gauge 3/4" diamond flattened expanded steel. (Bought an angle grinder for $10 at Harbor Freight and a $2 cutting disc for it.) Got the expanded metal 2'x4' sheet from local metal supply shop for $25.
Added a 2nd (lower grate) as well for optional diffuser/drip pan or to place the fire basket for grilling.
Cooking with her now (some rib tips I got on sale for $2.27/lb), using the new basket and notice the extra set of acorn nuts under the top set :)