Wasnt me that called it a ‘Butterfly Tail’ James 😉
I had seen the ‘Y’ config and contra props.
But it is still extremely close coupled.
Assuming the c of g is somewhere between the engines,there is virtually no keel area aft of the wing.
I was thinking about low speed/landing/take off handling,and the complication of the contra prop drive shafts/gearbox.
She is quite pretty in an unconventional way,but I would also imagine that the visibility from the pilots seat would be somewhat limited.

rgds baz

Bager 1968
I did realise it was a ‘Y’ tail by the way,above is a quote from my post after the one you quoted from re the fin /stability etc 😀