Ok, that sounds similar to my implementation for turning tile actors into ISMs and should work well. I toyed around with HISMs when they were added to UE4, but it didn’t seem to improve performance above regular ISMs. I’ll probably also switch over in a future update, though.
I love that you’ve added squads of units by the way! It is something I plan to do for a simple 4X game example. Did you encounter any problems when adding this or was it quite straightforward?