Thanks. What you are asking is now much clearer to me.
First, a little bit about how I play. I always pause when giving orders. Except for bombard orders/changes, I always create a save game before and after. I started doing that a long time ago when I was trying to learn the game, since I could then try something different without having to replay from scratch. In any case, I have maintained that habit until today (I rarely ever back track and try something different) for two reasons. First, it is invaluable when beta testing, since when issue arise I have reproducible examples I can turn over to Dave. Second, it allows me to go back to completed games later and cull out examples for tips.
... I guess was I was trying to ask is since I can't switch sides and see what the bad guys see ...
So, getting back to your question. That entire game was completed playing it just as you would when you purchase it. The planning and execution was done without any beta cheat tools. However, after completing the game, I thought their usage would help to better illustrate my point. Thus, the presentation using the beta cheat tools. You should have no problem achieving the same results that I did.
... ascertain what terrain features will actually afford me this LOS "protection"? ...
Okay, I went to the back of the HTTR manual to view the various tables of terrain affects to see if I could get you some documentation on this. However, the tables are really presented with symmetric LOS in mind as opposed to differential sighting. Thus, they only address the theoretical maximum LOS through the particular terrain type. There is a little note below one of the tables that says "Units moving and firing are easier to see.". So much, for providing you with hard numbers.
So, let me tell you what I believe to be true and probably is (both of HTTR and COTA):
(1) Open terrain meaning lacking buildings and/or trees will tend facilitate spotting of a unit present in it.
(2) Closed terrain such as woods and towns will tend to diminish spotting of a unit present in it.
(3) The lower the deploment status (halted units always start to go through the deploment cycle) the easier units are to spot. Undeployed -> Taking Cover -> Deployed -> Dug-in -> Entrenched -> Fortified Represent increased difficulty in spotting a unit.
(4) In conjunction with #3 movement makes units easier to spot.
(5) Firing makes units easier to spot.
(6) Units with AFVs or motorised units have a higher profile and therefore are easier to spot.
(7) Foot infantry has a small profile and is relatively harder to spot.
(8) Increased distance within the range of maximum LOS reduces spotting.
(9) Relative unit size impacts how easy it is to spot.
Now, that is what I believe and needless to say there are many questions as to how those things interact with each other. Also, there are whole host of other questions like:
(1) Is spotting ability reduced when a unit is in motion?
(2) Does firing at night make a unit easier to be spotted?
(3) Will overcast (dim lighting) reduce spotting capability in an assymetric fashion?
(4) Will weather such as rain as opposed to dry still conditions reduce spotting as it generates noise in the environment?
So, going back to your question of what did I know and how did I use it to create the desired affect:
(1) I chose a point of observation with a view to a major road that provided the enemy a way to travel along their axis of advance. With the severe movement restrictions that exist in COTA compared to HTTR, this is critical.
(2) The position picked was itself unlikely to directly along the enemy's path but rather adjacent to it. Making it less likely that the enemy would stumble upon the position.
(3) I chose an elevated position, since it would afford the greatest field of view over the area of interest. The proverbial "high ground".
(4) I chose woods (not an orchard or light woods) as it would offer the best cover to hide my presence.
(5) I didn't really have motorized infantry available to me, but if I did I would have still chosen an infantry company on foot. Why? In COTA, woods are impassable to motorized infantry. Also, infantry on foot should have a lower profile. (You could do the same technique with motorized infantry along the outskirts of a town.)
(6) I chose a position set back from the road by about 2-5km. This will tend to discourage unit from getting involved in a fire fight with small arms. However, if your intention was to block instead of observe, then you should be between 0.0-2.0km.
(7) I made sure there would be at least six hours or so before the enemy were in the area so that they would have time to dig-in.
(8) I made sure that their orders would have them take internal trails through the woods to get into position as opposed in front of the tree line along the ridge which might skylight them for the enemy.
There you have it in as much detail that I can give you.
Is it guaranteed that they won't be spotted? No, nothing is guaranteed. In fact a unit in the same tree line 3km to the North-West with the same mission was spotted and pounded without mercy by German arty.
You'll know it worked, as I did, if you see everything that is going on, but you are not taking any significant fire or arty.
Remember differential sighting also means you see them before they see you. So, if you had them spotted for six hours before they spotted you that means for six hours your guns could be hammering them. That's worth a lot.
Also, remember that even though your unit is spotted, a dug-in unit in a tree line is not that easy to dislodge without an actual assault. If the enemy doesn't assault their location, then they can continue to fulfill their mission. If the enemy does assault their position, then it means he has ceased making progress towards where he was really intending to go. Either way that company will make a significant contribution towards delaying the enemy's progress.
Well, that was quite a discussion. I hope that makes it all clear.
Never more! (I've had enough. Sliterine has raised mediocrity to an art form!)