"Caves!" is what you hear often at the beginning of the battle in this map – for a reason.
As with any other map, over the time players have figured that the caves side gives a better opportunity for winning the game, due to the terrain configuration and options for all types of tanks, including staying undetected for some time.
Way back, when a team was mostly heavy, players would clash on the factory side. Now, no matter of the team composition, solid players most often opt for caves and middle.
Also, when playing this map in supremacy mode, calling "A" is simply a selection of a side, not that a fast tank should cap right away. First spot, then move on.
"Spot middle!" or "Spot B!"
OK... spotting is the most important action at the beginning, and one of the most crucial actions during the entire battle.
But for this map? Besides Naval Frontier, not sure if one could find any other map to compare about importance of spotting middle and getting the control of it. Just watch how tanks that move on sides (either way towards A or C ) get sniped while having no clues about tanks that snipe them. Heck of a damage can be done with the good start in this map.
Choosing to move along the side only is the death trap as a single red tank that spots from middle can reveal the whole team.
There are times when teams can still score a win without middle spotting, but that is only when reds are "nubs" or simply unfortunate.
Another map where middle is IMPORTANT – better say CRUCIAL. Usually a medium or light tank, but a heavy or even a TD can spot middle at the very beginning, if no other is available. Spotting middle in this map from bush above base B area reveals if any tanks (heavies primarily) are going the heavy side. It also gives an opportunity to make some early damage and add confusion and sort of mess to a red team. As this spotter tank is doing its job, a TD can go to the back bush to snipe red's "above B" area.
The above approach is a recipe for win or at least getting a good start and control of the middle of the map.
This helps the heavy side to enter the battle with more confidence as spotted tanks become easy targets.
All in all here, spotting middle gives an opportunity to the team to push either side and strolls into the win.
The spotting job is best done by one or two tanks. Three or more is too many.
This map has quite a history from the perspective that an approach has changed rather significantly. In the past, it was team composition that would determine the side of teams' movement.
Dominantly heavy tank teams would always move towards A base zone.
Since some time ago, a lot of good players (aka unicums) will always opt for "C" side, no matter the team composition (almost). Anyhow, when opting for the C side, this map really requires medium and light tanks, as well as heavies, to go middle road, not via back. Not all but some have to go in order to spot and prevent red tanks spotting your back line where your TDs are. So many times it has happened that taking a rock/bush position at the back with a TD turned devastating as red tanks have already got to the point of spotting our back. Yet, they not spotted well.
The reason? Our spotters went back route which took an extra time. Operation "screwed."
Each player has to determine the role of its tank, being medium, light or a heavy. I excused TDs on purpose here as they usually take back positions. I say "usually" as in cases of fast TDs they may go shorter route to the middle of C zone, same as other spotters. SU-122-54 is an example. One thing to have in mind is a gun depression of a TD that may be a reason not to go, regardless of its speed. If you cannot aim and shoot properly from that position, forget it and never go that way at the start.