yeah, many use 1-2ml per day.
On the nicotine strengths, you can always cut it down with VG/glycerine/glycerol or PG, but can not increase it easily/if at all.
Note that some have allergies to PG, plus you'll have 'the rest of cigarette withdrawals' going on as well, plus possibly an 'adjustment period.' There's a good thread somewhere on this, but basically, some sore throat is 'normal' for most, some muscle soreness perhaps. Anything else, start doing some searching; it's possible you've got an allergy.