Sounds more like a
React To Contact situation than a
React To Ambush one. In the former you would want to give the surprised side a chance to deploy outside the kill zone and maneuver to engage the attacking force once contact was initiated; In the latter the ambushed force would have to immediately react and either gain fire superiority within the Kill Zone or assault thru the Kill Zone and establish a base of fire & maneuver to break the ambush and reduce the ambush site.
The best approach is to establish a mission/scenario objective (maybe even write it down), of what you wish to achieve with the scenario. This may or may not include your VC objectives as they will be determined later. You should be precise on what type of engagement you are trying to portray: Movement to Contact; React To Contact; React To Ambush; Probe an Enemy Position; Assault; etc. for each side, then attempt to produce a scenario predicated upon your understanding of the given situation. A lot of this I'm sure you do without even taking time to think about it, but it always helps to slow down and put your thoughts in order first. I have done this countless times (though unlike yourself, I have yet to submit a scenario for publication) in setting up training programs/situations for various Armor & Infantry units in training exercises. Just food for thought. (BTW, have you seen the "Opponents Page"? There is a guy in Scotland looking for opponents.)