Personally, I'd find somewhere else, like an ex-pen for him to spend the long periods of time he must be confined and then work on gradually conditioning him to the crate...open door first like you're doing with the food. Then close it for under a minute while you sit next to him, then let him out. Then gradually close the door for just a little longer while you still sit close. Then shorten up the duration, but go a few feet away. I'd spend 3 - 5 minutes several different times during the day or night just getting him use to longer spells and having you be away from him, but gradually. Only step away for a few seconds, then return and poke a treat through the grate. Frequently, quickly and like it's a game. I'd be careful not to ask too much too soon so that he isn't as apt to throw a tizzy fit and won't associate being locked up in the crate with a rotten time.
Anyhow, it's hard for a pup to immediately have to spend a long time in a crate if he hasn't been conditioned to it. Just like teaching a dog to wear a muzzle or getting him use to something else unpleasant. It seems to go better if they're gradually conditioned to it.
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