The widest bodied trads (from all my measurements ) appear to be the 98 on centrelock wheel equipped Plus 8's.
Yes that was true Dave had us all measuring prior to his book I think and ours proved to be the widest rear wings of all, the tubs of the era being identical, there was a 5mm discrepancy left to right on mine so I know it's a Morgan.
Not wishing to start the whole “get the tape measure” again; but!
When Jays and I compared the interior tub width of his 2009 3 ltr Roadster with my 2003 4/4, there was around 35 mm difference.
We measured just behind where the doors close.
My 4/4 being narrower.
Bud
4/4 - Stanley