Tutter, as you know, I have two boys. They also have different characters. DS1 was Very Keen to sleep (he couldn't, often, because he also used to have sky-high temperatures (41 degrees) each time he cut a tooth, so I used to sit up with him, rubbing his hot back, offering him sips of water and hoping he didn't puke again while he whimpered softly and tried to sleep).
DS2, on the other hand, will NOT do things unless he wants to do them and never has done. Sleeping was Not His Thing for the first 15 months of his life. He slept through once in that time, the night he was four months old (contrary chap - maybe he was worried I'd spoon wallpaper paste in his mouth if he woke that night ).
Don't think I'm saying my way of doing things was right - I was A Bit Mental for the first year of his life (yeah, yeah, shuttit you lot) - but I felt there was honestly no point leaving him to cry, because he could keep himself awake for hours at the best of times.
Do you have any help? Other than your lying-down DH? Can you say to anyone "Look, I really need some sleep, so once a week, I'd love to have a morning in bed, so please, please, for the love of God, take the boys and keep them out of earshot for me, please, please, please"?
It is hard having two little ones. It is harder still when one of them doesn't sleep well. I know we have a similar age gap and I promise it does get better.
Having said all that, if you're 100% resolved that CC is the way forward, there's nowt I can say that will change your mind. But there are a lot of us who didn't use CC and muddled through and it was OK to do it that way too. I have been following this thread and didn't post until you said about the characters of your boys, because it rang a bell with me.