Kelle, look after you too. You sound exactly like I felt with Mitchell. It is horrible, and enough to tip you into depression.

No, controlled crying has no guarantees, nothing bloody does or we all would'nt be here. CC was big for awhile but alot of parents found it too hard on them and the babies.
Sometimes I let DS cry for a little while as he is so wound up. No specific times, it depends on the way he is crying.
DS is very easily overwhelmed, I noticed this when he was very small. I was advised to take the mobiles out of his room as they would distract him from falling asleep.
Patting drove me spare too. The SSHHH thing we always use, and most of the time I can just stand at the end of the cot and shoosh.
DS is a very light sleeper, so often a small radio in his room on a classical station drowns out any outside noise. Quiet but not too quiet.

Good Luck, your not the only one losing the plot, but again, make sure you get some time away or be able to do something for yourself or you will wear down further (if thats possible, poor love)