From: Western Australia
It's been several years since we did GJS, but I recall that we were both about 30-40% across the map as the Allies.
As for turns completed, we were both getting concerned about time remaining for the Allies. As a reference point, in our German campaigns we both had that fairly unique recon (Aufklärung? included a bunch of armoured cars) battlegroup enter as fresh reinforcements on the western edge of the strat map. I recall that we regretted not being able to play on some of the western maps, as they looked quite good.
My opponent in these twin campaigns tends to be quite aggressive, and his losses tended to be much higher than mine. In my Allied campaign I was trying to find a balance between offense and conservation, but even I was feeling the pinch. As the campaign continued, I had to use my reinforce button for most units, and applied as much pressure as I could. However, I've found CC is not really a game where you can just throw units in, to force a situation.
I found that to efficiently take a map off a good human opponent would take about 3 battles in most cases, and my opponent would often do effective counter-attacks once I had taken a map, so we would see turn after turn of fighting along a generally static front line.
As a contrast, I remember I later did an Allied campaign against the AI, and was able to push across the whole strat map well within the time limit.