There may be a big difference between the top 0.01% of g and the top 1% of g (or there may not). But IQ is only a loss abstraction of g, and it almost certainly lacks the resolution to say how top 1% of IQ and top 0.01% of IQ actually correlate with g.
(In contrast, you can be relatively certain that someone in the top 1% of IQ has a higher g than someone with bottom 50% of IQ).
(In contrast, you can be relatively certain that someone in the top 1% of IQ has a higher g than someone with bottom 50% of IQ).