It's clear you have no idea who John Dunkerley is . . .
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I'm really mystified why so many insist on a wide, loosely goosey definition of the Decca Tree; it was very clearly defined by the people who invented it, and wasn't any old triangle of any old mics.
There isn't anything 'more ways to skin a cat' about it than there is about ORTF, DIN, NOS, etc. There was a bit more variation in the Tree at Decca, but it was quite 'standardized' there whether you like it or not.
Use any tri-config with any mics you want, it just won't be a Decca Tree. Same if you use a pair of subcardioids 5" apart, aimed 90 degrees, it isn't ORTF, DIN, or NOS.
If you shoehorn a Chevy small block into Ford truck, it's no longer a Ford, is it?