I've done it many times. The problem we run into, is if the yolk isn't absorbed all the way, or the blood vessels around the inside of the shell are still there, that he will bleed to death.
On the other hand, if he is ready to come out, and just stuck, he might suffocate trying too hard.
Knowing the difference is hard, especially when the only way of finding out is opening the egg up.
If he were the only one left at 23 days, I would yank him out.
But since there are others that are slow, It may be he needs more time.
DO NOT TAKE THIS AS THE RULE.... I would make some small cracks along the hole where his head is.
If you see blood STOP. Another problem is taking your time, VS letting it get too cold/dried out.
If you can get the zip all the way around, it's possible he may pop right out.
Do you know if any of the others are fertile or not? Did you candle?