There was strong sexual selection in Polish females, that's why they are so beautiful. Polish men are damn ugly bastards. This contrast proves that they evolved as a nation.
I don;t fully follow your reasoning here... anyway, Polish women, and men, are of all shapes and colours, in reasonable limits. Ukrainians are more uniformed, as are Germans, the English, Italians, etc.
No such thing as a full Pole. Everybody could dig out some foreign ancestor, and let's not forget that the nation wasn't really formed until somewhere near Renaissance.
We have to carefully extract Slavic genes into alcohol,
Aah, now you talkin... Alcoholic extract, pure essence of the Slavic spirit! Rright! :)
Come to think of it, I vaguely recollect such experiments being done... on numerous occasions even... so you've hit the nail in the head, yes. The common Slavic thing is that deep conviction, based on a long and extensive research, that we truly know what being Slavic means, since we must've seen it so many times with our own eyes! :)
Edit:
They love their ethanol.
That's a very mystic thing, man. A quest to the roots, like. Don't take it lightly