My el-cheapo ($5 on sale) lattice top cast iron steamer works like an el-cheapo model. It doesn't give off near as much steam as an open pan of water. I think it has a small bump of cast material on the bottom that has been porcelained over which prevents the bottom from siting flush against the stove top and benefitting from the full transfer of heat. I could grind it down, may still do that, but I hate it for more than just that. Instead I realized I had a larger, vintage cast iron dutch oven pan I could use. It seems to liberate the steam quite well. But I'm wondering if I should try to coat the bottom in porcelain paint to help keep scratches and rust down to a minimum? Is this possible?