http://www.youtube.com/watch?v=3R1PjiXOK8Q&feature=youtu.be - Stage 11
http://www.youtube.com/watch?v=-UHuhEOE6ac - Stage 12
http://www.youtube.com/watch?v=rhEaSVNNubg - EX Stage
I've got those two stages on my channel, with the time each scene starts in the video description. (Might upload Stage 11 just for the heck of it.)
I'll get some actual advice written here after I look them over:
8-4 ~ Watch out for her ramming into you after the picture is taken, and try to take the pictures right when she makes a new sun.
8-6 ~ There's a specific pattern that works very well. I found that every other picture would be used for defense, and try to get two suns when you take the defensive picture. Also stay out of the middle. Keep the suns on the edge.
8-7 ~ Take a pic the instant she fires, hopefully near the center of the screen, then run to the side she's moving away from. It's quite like something Aya did in StB during Eiki's last scene.
9-1 ~ Memorize the first part I guess. Don't be afraid to take many defensive pictures in the later phases just to gain some ground.
9-3 ~ A funny one. Notice where it will be safe to stand, then work your way to that spot. DO NOT rush there immediately or the aimed bombs will just make it unsafe and you'll have nowhere to go. Not sure if you can take a pic the instant they explode on top of you to save yourself.
9-4 ~ It seems to follow some kind of pattern(?). I think the DNA seems to follow Koishi or something. All I really know is look out for when she tries to smash into you, and then really get the hell away from her. (Far away)
9-7 ~ Just laugh at it, because it's laughing at you.
10-8 ~ Stay as close to Iku as you can, and take photos as rapidly as possible. It's much easier with Hatate.
12-2 ~ Try to play it safe and take out the clone immediately, I recommend seeing what I did in the vid.
12-3 ~ You need to take pictures at very precise moments to avoid being screwed over.
12-4 ~ Get familiar with what the pattern becomes as the scene proresses. Shouldn't be too tough, I don't think.
12-6 ~ Keep your eyes focused up near Nue, and don't worry too much about the blue bullets. I tried to think of myself as aiming for the spaces rather than dodging the lasers.
12-7 ~ Maybe it's good to let the rectangle shrink before taking a picture so you don't get swords, though personally I didn't do that at all. I know you should stay close to Byakuren though.
EX-1 ~ Very easy if you take pictures at the right time. Just check the vid for one way to do it. You wanna use the giant amulets to clear the bullets, then clear the amulet yourself while also getting Reimu in the shot.
EX-7 ~ Reimu aims herself at you, and the walls she comes from follow a clockwise pattern, so you can predict her easily. Just sidestep and recenter. Her amulets come from the point on the wall she appeared from, so keeping everything centered is very helpful. (Also, a slight diagonal movement in any direction will invariably evade her, but it looks more badass to do what I did.)
EX-9 ~ Well, it's super easy. Just do what I did I guess.