Questions about adding more insulation
I plan on adding more insulation to my attic but have several questions. My house was built in 1912 and originally had what looks like vermiculite insulation, I'm not sure how much or how deep this is. At some point 4" fg bating was added and is approx an inch or so above the joists but there is no vapor barrier on the battings. Should I remove the existing fg battings, lay down fg batting with a vapor barrier and then relay the original fg batting perpendicular to the 1st layer? Or just add unlined battings to what's already there?
Also, the attic has old electrical wiring that's attached to ceramic knobs. These may be dead wires as some upgrading has been done to the wiring downstairs but not sure if this extends to the 2nd floor. Some of the insulation is touching the wiring and in places the wiring runs across the top of the insulation. How should I add insulation around these areas?
I planned on doing this myself but need suggestions and ideas on how to proceed. Thanks