If you have back issues to OGR....go find Run 255. My layout was the cover feature with lots of pictures inside. That layout was completely ballasted with rubber ballast in (2) sizes. After installation, it was weathered with diluted India ink. I always got a lot of positive comments.
My new layout features real granite ballast by Dennis Brennan. Hands down, the best you can buy. I would never use anything else.
Yes...I glue it all down. Spray (soak) with "wet water" and apply thinned down white glue with a squeeze bottle. Do a search on the board, there are dozens of posts on application.
I never understood making a permanent layout and then not cementing the ballast in place. I just cannot imagine constantly having the ballast "moving around" or having to dress the ballast edge unless you never touch the layout. Just my opinion.....but then I also put grape jelly on my egg and sausage sandwiches.