So just to flesh out how I saw the Roman Civil War format, it is something like Scenario X, but a little more programmed
Roman Civil Wars
Step 1 - determine first player
Each player rolls 7 die and the highest number of Leader symbols goes first in every subsequent step.
Re-roll ties.
Step 2 - place terrain
Each player has a scenario specified set of terrain tiles (e.g. 3 Woods. 2 Hill and 1 Rough terrain tiles)
1st player places 1 terrain tile on any
clear hex within 5 hexes of his baseline. 2nd player then places 1 terrain tile on any clear hex within 5 hexes of his baseline. Tiles are placed alternately until all terrain is placed.
Step 3 - place standard units
Each player has a scenario specified set of units and leaders. (e.g. 3 LI, 2 AUX, 4 MI, 2 HI, 2 MC and 2 LDR)
1st player places 1 unit or leader on any hex within 3 hexes of his baseline. 2nd player then places 1 unit or leader on any hex within 3 hexes of his baseline.
Units and leaders are placed alternately until all given units are placed
Step 4 - place optional forces
Each player has a scenario defined set of options to choose. For example
1 HC or 1 HI
1 LC or 1 LS
1 LB or 1 HWM
1 LDR or 1 Command Card
1 WAR or 1 MC
Each player starting with the first alternately chooses which option they select and place the unit on map within 3 hexes of their baseline. Command cards are drawn into their hand (and can be viewed).
Step 5 - draw Command Cards
Each player draws 4 Command Cards

which add to any Command Cards already drawn. Players that selected an extra Command card have an increased Command. (e.g if they drew 1 Command card in Step 4, their Command is 5)
Step 6 - 1st Player moves first
Step 7 - Victory Banners = 7 (unless otherwise specified)
Thematically, the Roman Civil Wars were a knockout tournament until one is left standing. Draw would be random pairs. However, Round 1 could be a dry run, just to get the kinks out.