I, too, very much like the skirmish concept, for both main and side matches, wherever the range layout permits it to be done safely. Our local CAS range has individual bays with side berms, and we like to use downrange movement in scenarios.
With that experience behind me, I'll "state the obvious" - placement of loading and unloading stations is critical when this type of movement is considered. (Our side berms permit us to orient the tables so that gun muzzles are pointed into the berm, rather than downrange as they usually would be ..... Alternatively, if vacant bays are adjacent to the stage being shot, the tables in those bays are used, for even greater safety.)
Of course if movement downrange is possible, movement
uprange is equally feasible (..... and necessary, for that matter .....) So, although I'm sure this has already been considered, I'll again "state the obvious" -
withdrawal (retreat) movement is just as appropriate to our shooting style as advancing movement! In other words, the shooter can start in a downrange position and "withdraw" toward the static firing line, or can advance from the firing line and then retreat .....
Lots more room for creativity ......