I would start with PG, if possible. Or distilled water, if not. If you are a huge fan of Throat Hit, then use vodka of Pure Grain Alcohol (PGA).
I would put your
juice in a smaller bottle, 5ml or 10ml, and add the dilutent a drop or 2 at a time. Don't add too much too soon.. take your time.
I use a tank from Valley View Vapers and use 70/30 VG/PG all the time without a problem, but I've never used a vivi nova.
Good luck and go slowly.