Recon Mission Stage 3 is due to start tomorrow, September 17, and end September 24.
As this is the final stage, we know what the maps will be:
Map name: Canyon
This map was playable on the test server during the Recon Mission test. Heavies would fight in the South-West section of the map, Lights would fight for the hill (South-West of the centre) and mediums would fight in the North-East. The open field (North-East of the centre of the map) was not used much, but there is cover for risky advances. If you control the hill, the North-Eastern areas are just outside of render range, but with a little map knowledge, you can blind fire enemy tanks (and vice versa).
Map Name: Oyster Bay
This is another 1300 x 1300 map. Heavies fight just south east of the center of the map in the lanes, tank destroyers cover the airstrip, and mediums try to find firing positions. If you are in a fast vehicle, you can get to the south-eastern most point on the farms and spot and shoot across at the heavy tanks as they fight. This is a dangerous position, and you are almost guaranteed to be spotted getting into position.
Map Name: Avalanche
Heavies fight in the Eastern side of the map, with Tank Destroyers attempting to shoot over their shoulders. Mediums will fight in the Western side of the map. There is plenty of terrain to hide behind, but I found people would insist on sitting on the red line out of the render range to shoot at spotted enemies. It is possible to advance under the ice sheets in the center of the map, but you easily get caught in a cross fire, so this is risky.