I can't directly answer your question because I don't think there is a concrete answer, as previously stated, all dogs are different. However, I can share our recent experience. New pup New Years day. Most of the siblings were still with the breeder, No prior crate experience, etc.
We have him in a 38" crate. I did not want to try and divide it. He has bedding and about 3 stuffed animals in the crate with him at all times. The crate is right beside our bed. I lay my house clothes over it in hopes he will notice my scent. I also put my socks in front of the crate just out of reach for the scent. I don't know if any of that makes any difference but I want him to know my scent as we are currently bonding, bonding, bonding.
This is our first male dog, all others have been female.
1st night, he cried for quite a while, not all night. He woke up about 2:30am and started crying. I sat on the side of the bed until he settled down, then we went out and pee'd. He woke me again at 6:30 am. I sat on the edge of the bed until he stopped crying, we went out and pee'd and pooped.
2nd night, He cried for 10-15 minutes, then settled down. He cried a little sometime in the night and I fell back asleep on him. He cried again about 6am, when he settled, I let him out and we pee'd and pooped.
3rd night, He whimpered a little, settled down and woke me about 6:30am.
Each day I have been putting him in the crate when I shower because I can't watch him. Blood curdling cries each time but settles down in a few minutes. Today when I crated him for my shower, silence. When I got out and got my socks on, which is always a challenge if he is in the room, I opened the crate door and he laid in there 5-10 more minutes before he came out.
I have to say this is probably the easiest crate train I've done, the last dog was pretty darn good but I think Dagr has been just a little easier.
Dagr "Dag" 11/07/2013-