Hi, wade on in to the NICU pool!
I work at a level 2, so I can't speak for level 3 people. Our usual orientation is 3 months. This includes all NRP, STABLE, PCEP and whatever else they feel like throwing in. I seem to remember you working L&D, (???? did you???) so you probably are at least comfortable with well babies.
Our staffing ratios can really vary though depending on the acuity of the baby. feeder & growers normal is 3-4 babies per RN. Doesn't sound too bad until you have to PO feed everyone, plus give meds, etc. Most of our hood, CPAP or vent kids rate 2 or 3 to 1 RN. It really depends on how stable they are.
Our sickest kids are 1:1--- these are the ones that sometimes end up getting shipped out for ECMO, or Hi-frequency.
OK, so I don't think I was much help.