nahh..I had my frustrations here too,but I was doing it wrong. I binoculated (not a real word..is it?) to two points where I know the tanks will end up.

First place is far back beyond the bridge (alot of tanks resides there over and over.) Keep clicking there and watch your back every time. You'll noticed just beyond the horizon, another tank just over the other side of bay is coming toward the bridge. Don't bother trying to get the planes to hit it (you could but need timing) That tank will end up on just on the other side of your tiger tank. That's the second spot, aim there but only when the tanks are there.

I finished the game on hard, dunno how easy it gets a notch lower or two. This is how I pass this sub-mission. I went after the tank all the way in the back first, then I turn around and drop a nade in that stairway (enemies will back off if you're early with the nade, they will charge you if you're late) then I went after the tank in the far back again, also noticed the other tank over the bay is coming up to the bridge, I pulled out the thompson and took out two guys coming from behind. Then I aimed the binocular at the far back again, noticed the tank coming on the bay, I then threw another nade in the stairway and aimed binocular at the second place. Killed the two guys sneaking up and then repeat from the begining.

If you're outta nade, good luck. BTW, pay attention to tiger tank health, if you're tank is down to 30 by the end of second nade in stairway...start over.