so, I find IEI-Fe's to be easy to spot.
I find IEI-Ni's impossible to spot. why? because they VI as everything but themself.
I told my IEI friend that he looked like an LII. He then tells me, "hmm, well my dad is an LII, and I hang out with him a lot."
Which brings me to another point. I have this hidden ability to transform into whatever personality I talk to, if I do it hard enough. So hard.
I would only imagine my dual would have an increased ability to transform into shit they actually aren't.
So now I'm under the impression that IEI-Ni's are impossible to VI because they take on physical characteristics of whoever they are hanging around with most often.
An actual ninja (who kinda looks like mclovin) recently told me, "You can't VI a ninja, because they don't think."