On the unflavoured front - when pre TPD I could get 32 strength Greek Nicotine in a 50/50 PG/VG mix in 100 ml bottles I used to mix it with the same 50/50 no nicontine liquid and IMHO, depending on the atomiser I used it in, its taste was reminiscent of my two old favourite British Cigarettes Senior Service Plain ( if used in a Nautilus Mini ) and Players Medium Plain if used in the little E Leaf Tank ... but British "Virginia" tobacco cigarettes were very different in taste from U.S Brands and style.
Unflavoured liquid never gunked up coils with me; flavoured coloured liquids would get me a week out of a drop in coil; clear unflavoured would get me 6 weeks.
When Cromwell who used to post on this Forum told me about the 6 weeks, I didn't believe him ... until I tried it for myself.