You poor thing. It is so draining not getting a proper nights sleep AND having to work on top of that (I can only imagine how hard that is, it's hard enough staying at home).
I only let him cry it out when he is past it. For me that means he is not happy being cuddled and I can't cope with the screaming/crying anymore. So I pop him into the cot ( and usually close the door) and give him and me a chance to calm down (I know it is supposed to be even more stressful crying but when he is crying either way what difference does it make) and he usually falls asleep in 2 or 3 minutes (this is usually only during the day tho)
Are you feeding him when he wakes overnight? I found that I had to go back to feedng Flynn overnight when he was between 10 and 11 mths. He would just not resettle otherwise.
I don't really know what else to suggest. Have you tried or is co sleeping an option? I got to the point where if he woke more than once overnight I would just bring him into bed with us. I find it much less draining to comfort etc when I'm lying down.
We still use a dummy and generally if he wakes overnight he just needs his dummy put back in and he is straight back to sleep.
Personally I have never done CC overnight, usually if he is really unsettled DH deals with him (he has the knack...seriously he's amazing!) I think it would be too stressful.
Hope you have a breakthrough soon.