We can talk here for the next hours, simply try it, i’m working that way since months, actually since i figured out that i’m getting the best lightmap results this way. It works also perfect for more complicated round and cylinder meshes and when using higher lightmap resolutions you get almost perfect results.
Somewhere in the archviz section a UE4 developer wrote that you don’t have to keep the form of the mesh for your lightmaps, you can strech them etc… That was the start point for me to try it on round / cylinder meshes.
Actually i’m not here to start a debate 
I just wanted to share my way of doing things that worked for me good. Every one is free to try it or to use a different way to handle lightmaps.
ZacD, here with more shadows… still with 64 x 64 lightmaps. I can’t build a fence “thing” cause my cylinder has no face on the backside. It was just created to show off the effect / ligthmaps. But it’s a very simple mesh, i think every one can try / experiment with it.
