Which is the best BMI for sprinter and 400m dash?

Because I'm in diet, I'm also thinking which would be the best BMI to reach my goal (400m in 59.9 sec!! or more likely under 1:15 that is my personal best!).

Looking on internet I found this very interesting paper in which authors studied the BMI of the top class athlete of different discipline and even the height.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3934974/

Authors found an high correlation between Speed and BMI (r = 0.71) in world-class runners and moderately with height (r = 0.39).

More specifically they found that the highest percentage of top athletes have the following BMI:

100m 24 kg/m² 
200m 23 kg/m²
400m 23-22 kg/m²
800m and 1500m 21 kg/m²
3000m,10.000 and marathon 20 kg/m²

So I should achieve a BMI between 22-23 kg/m² that means 65-68Kg follwing the computation form this site: https://bodykey.it/public/bmi  ... probably is too hard at my age, anyway never give up!!

Today I'm 84.6 Kg :D