Hadn’t even thought of making a Catan-like game. Sounds fun. Maybe as a side project in the distant future. 
Graphical niceties I am generally leaving to the future. Still not sure how I will handle tile boundaries. There are some pretty cool dual material effects in the content examples that I would like to try if not too GPU taxing. Perhaps the simplest method would be to use decals on the edges to bleed vegetation and other things. Actually, if I had proper UVs set on my textures the edges would fit together much better. Either way I will work out some method for smooth tile transitions.
Yeah, all tile data is kept on a series of arrays that are indexed in a specific way. Index 0 is the bottom right hex for every array that holds map info. There is a screenshot of the spreadsheet in the first post.
Right now I have a line trace set up on right click that hits the collision volume, gets the index of that volume, and then I can use that index for anything. Right now it is set up to chop a tile’s trees down. At some point I will use UMG for that interaction, but for now right clicking is all I need. The overlay you see in the tectonic images is just the collision volumes that I am making visible and coloring to show the plate boundaries.