A sub has roughly 35-40 enlisted nukes (so SSBNs would have 70-80). A carrier has roughly 350-450 (Enterprise has more I think). The surface numbers may be a little off. When I graduated from prototype in 1986, if you had not volunteered subs before NPTU, you were going surface. I knew several guys who had volunteered subs that still went surface. At the time they were manning up the Ike so many a baby nuke got sent there. My uncle who took to me to the recruiter had been a submariner and recommended I volunteer for sub-duty. My original plan was to be an submarine RM. Once I switched to nuke, I maintained my sub-vol.
Gamecock answered your other questions.