I think the main reason for spirits are more "forgiving" than beer is the fact that you loose a lot of liquid from drinking beer (it´s all the toilet visits
) and dehydration gives headackes...
I don´t have a clue how to avoid hangovers. I only think they can be reduced; never removed completly. I did try something called "gopal party cactus". They says that it "might reduce hangovers". First time i tried them i didn´t really feel much diffenrence (maybe a little but i´m not sure) and the second time i tried them i had the worst hangover of my life the day after. Anyway i think that the main reason for them to work is that you have to take them just before you go to bed with.....a big glass of water. No wonder that they "might reduce hangover". So does a big glass of water so i recomend that you stick to the water before bedtime...