VG70/PG30 Base 9mg. - 10ml.
If you just want 10ml. PG/VG base with 9mg. nicotine, you can simply unscrew the lid and add up to 2ml. aroma (20%) directly into the bottle. Then shake the bottle. It's easy!!
The liquid should ideally mature for a few hours/days before use.
Normally, pg/vg bases are mixed with approx. 10% Aroma (which is pg-based) to add flavour.