Best to start low about 5 mg/ml and work your way up the e cig gives a slower kind of nicotine dose. You do not get the initial rush like a cigarette so take a rest between drags and see how your mum gets on. It can creep up on you and if you over do it it can take 2 to 3 hours to feel well. Nicotine has a half life of about two hours. Ie half of what you took will be gone in this time. 5 mg/ml is a very low amount and I really do not see her having an issue with an overdose. I will list some symptoms just incase. headache, nausia, feeling hot, shakes, dizzy upset stomach and racing heart. This is not to scare you but just to keep you informed. I love my mum and I'm sure you love yours to. If the 5mg/ml is not doing it for her try a little higher strength untill it stops cravings or give the pleasure shee needs. A small increase is oftern all you need so prehaps 8mg/ml next time. At low levels the
throat hit or smoking sensation will be verry little and I only get a TH at 10mg/ml or more. The TH is mostly to do with nicotine and is caused by the
throat mussles contracting due to the nicotine hitting them. Have fun mixing and double check your math before mixing up, try a few ml at a time and if you go wrong it is not so costly. Also keep a record of what you mixed so you can repeat or ammend levels as needed. hope this helps a bit regards Rob..