G'day Terre , I was smoking 30 odd med-high ciggies a day , I find that 18 MG suits me not too badly so I would second Lu ...16, 18 24 ish???
( oh and I soooooooooooo wanted to answer thusly ..... "well I have always been partial to a 1948 MGTC ...far classier than the MGA's and MGB's.... " )