I created a little tool to populate crowd along a curve , this is very usefull especially when you should create army formations , or give a specific shape. The tool allow not only to choose how many people you want but you can also choose how many row expands the formations . For default the agents takes teh curve direction as orientation but you could also inverse that direction. Also the tool give you the control for fixing the distance between the rows and by plug a geometry you could also use that geometry as a bounds to create negative space, and finally you could adapt to terrain .
In the following images/video you can see the tool in action.