I think that the ones which behave the best are the heavily body-sized papers - the 'floaters'. I now typically only treat the Fabriano Extra White, Rives BFK, and Whatman's watercolor paper with the oxalic acid. The others such as platine, COT320 and Stonehenge do better with just straight double coating. Reports from some people are that diluting the first coat with 1/3 to 1/2 the volume with distilled water works fine as well. I just bite the bullet and double coat - which is much easier with cheaper palladium!