It's all wild guesses. Da Vinci never took an IQ test.
My wife remarks that we do know the IQ for one modern genius, Richard Feynman:
His measured IQ was in the high range - 124 - but not what IQ test-makers consider genius (135+). Contrary to traditional thought, but consistent with research findings, most people recognized as geniuses through their work do not have IQ's in the 135+ range.A lot of what makes us call a person a "genius" is their creative brilliance - not their general intelligence as such.
Of course Feynman started out smart,
but something more on his part
made him a truly stellar