Very cool combination of tools to get this result. For added realism, you could vary the shapes and sizes of the individual stones so that they created a more natural look. Even without that, quite impressive!
I’m not sure what happened between Steps 6 and 7…seems like the wall looked great in step 6 and that you just need to remove the “crevice” group. Somehow in Step 7 it’s less natural and the weight of dropping the rocks with MS Physics is lost.
I’ll have to try that method as I use Skatter currently which is fast to get a simple wall but takes a bit more effort to get them to appear “stacked.”