50% humidity is low at hatch - I like to have the humidity closer to 70% at this stage.
Have you seen
@pete55's very comprehensive
Goose Incubation & Hatching Guide? Another of his guides (on humidity during incubation) is
here.
Assisting in a hatch is risky, but it can be done.
@Pyxis posted this
guide that will be helpful if you choose to assist. If you do, it's very important that you go slowly and carefully, per the guide. The gosling may not have absorbed its yolk sac yet, and premature hatching can have serious consequences.
Best of luck with your hatch!