thanks for the replies, I think
...but is that a 'no' ?
Just thought that with a whopping big single engine on one side which is capable of keeping things flying, the increased VS area with 1/2pv^2 and centre of pressure higher above the root might cause the bending moment to increase such that 'clever' design might be necessary at the root (with the suspicion that 'clever' might = 'too clever' and limit design margin in extremis).