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I adjust the low wine pH to above 11 to hydrolyse the ester ethyl-acetate. This ester contributes to the hot (burn) of vodka and it's difficult to remove using normal distillation technique because its boiling point is close to that of ethanol.
After distilling the high pH wash, the spirit comes out at a neutral pH. I've done side-by-side comparisons and found that the high pH wash is much better. There's deeper reading in other threads within this forum.

Harley,
there are dozens of studies about the volatility of congeners in spirits. And about the relative volatility to the one of ethanol. Volatility is the key word here, not bonding to water or boiling points.
Those studies is what you should searching for. They should answer all your questions (except the pH question) if you dig deep enough.
Don't look at boiling points. There are substances in the heads with a boiling point of way above 100°C. The boiling point of a pure substance has no meaning for its volatility at low concentration.
And you should read more about what the congeners taste like in general. Burn on the tongue is more likely due to acids like acetic acids than due such a very volatile substance like ethyl acetate. So more due to tails than to heads.