Best handling car was the 4/4.
My experience is exactly the same. I have had a Class B ex race Plus 8 (just like Chris races today) and a well sorted 4/4. Tried them back to back at the MSCC track day a couple of years ago. The 4/4 was definetly the better handler although the Plus 8 was way faster per lap due to grunt and absolute roadholding due to wide tyres on 7" rims.
Significantly the 4/4 although a 1999 car was on the 'narrow' chassis. If you want a well handling Morgan (fun to drive but not necessarily the ultimate roadholding) then the best (in my humble opinion) is a narrow chassis car with narrow tyres (Avon CR6ZZ are the best narrow choice).
BTW the latest production cars are on a wide chassis. The front end is narrower than the Plus 8 and hence the better handling comments about the Roadster. There is a view by some that putting wide tyres on a trad Morgan is a bad thing as it has a negative effect on both ride and handling (albeit not ultimate roadholding).