BtheChange,
I am going through something very similar right now. (like literally TODAY with emails going back and forth with lawyers)
I don't think what you are asking for is unreasonable. You have very legitimate concerns and proof of his drinking. I have always remembered a post from Lillamy in response to my questions about divorce and custody that said she regretted not asking for stronger protections.
Please continue to use this place as a sounding board. There are moments when I have felt myself backpedaling and wanting to appease him (it's what I became accustomed to and I really don't like conflict). Thank goodness I've had this forum to keep me on track.
With regard to knowing or not whether he is drinking.....I was there too. He was very much a closet drinker. Then, it would start to show on him and I would confront. He'd white knuckle it for a while and pacify me. Then he would switch his booze of choice and hide in the basement to consume it. Again, eventually it would start to show again. An ugly cycle, it was.
Hang in there
Sending hugs
MamaKit