Ditch the helmsman and one of the watch qualifications from your list. I would have and extra torpedo and a extra flak.
The gunnery for the weapons officer I'd change to repair. You have a watch officer and a petty officer with gunnery qualifications. That should be enough. This will also give some flexablity when, at a later stage (if you make it), you need to change your layout of your sub so it has no deck gun. You can then replace this crew member with one with a flack qualification, as this is eaiser than replacing an experienced officer.
Play around, you might find a better combination that what you have listed. Having as many officers and petty officers listed with repair qualifications is a good idea, I learnt that the hard way!
