I buy the extract and mix at 10%. I drip my juice, so if I tanked it, it would be more VG. Maybe not 70%, more like 50 or lower.
At 70% pg though, you will get that throat hit, a smoker is used to. Maybe it won't be so bad for her at the start.
My wife uses my old Kanger Aero V2, and has for some time. She is a MTL vaper, and I am not. We top it on a 30 watt device. She has a 30 watt Sigelei and a 30 watt IPV. She only runs a 1.8 OHM coil at 9 watts.
She isn't much of a collector of devices, as she likes what she has. She can't lung hit at all, so I am the one with a metric shit ton of devices and atties (all lung hitter stuff). I can't be of much help with the Innokin, as I am not familiar with it.
Be aware though, most people that kick smoking in favor of vaping, tend to move away from tobacco flavors. It reminds them too much of smoking after a while. Me and my wife, both still all day vape tobacco flavors.