The tool from epic is reasonable good but it relies on already existing uvs that it can work with. Lets say you have a small building where you box mapped channel 0. The epic tool will do a pretty good job for the lightmap.
If you want to do a quick lightmap in 3dsmax then flatten does usually give good results. Make sure the gaps are big enough between the charts. They need to be at least 1 pixel. For a 128 lightmap I use a 0.015 for the distance in 3dsmax (with rotation unticked). Does that make sense?
It depends on the object. Flatten works well for buildings. Top/bottom mapping works good for a terrain base. Organic stuff probably just needs a rearrangement of the first channel. There is no automatic tool that does everything for you but this might be a good start.