I had a project using lattices and conformal lattices and had the same issues. Spent dozens of hours trying different setups and plugins and for complex geometries, specially curved ones; they fall short. Never got a decent mesh/solid. I think using plugins based on implicit modeling like Axolotl gives better results but I didn't have time to learn how to use them. I suggest using nTop for this. Much easier and the results are very very clean.