Divorced couples need to learn something, and the faster they learn it the happier they will be:
You can't control how your ex parents your children.
Unless you think it would be a good idea for him to control how you do, drop it. You will certainly have different ideas, different values and different approaches. You have to find a way to accept this or you will make yourself crazy.
While I think leaving a child to cry is cruetly to humans, lots of experts disagree with me, and he will certainly not be taken away by child services for having cried for a few hours. Whatever falls into the range of 'good enough' is outside your control.
The only thing you can do is love your child and do what you think is right for him at your house. He will adapt to the different rules and expectations, with less difficulty than you'd think. Probably with less difficulty than you do.
Children are not that easily confused. It's not as if you guys look identical or anything.