Hi DovMal,
Weixiang is right. If groom is born Rooster yr, 2011 is not a good yr for marriage. 2012 will be better.
As for which lunar month you need to avoid, this can only be determined using Bazi (ie your birthday and time of birth), not the Animal zodiac sign. That is wrong, very wrong. So what you heard or read is all wrong
To answer your qn: "If so, why people still using tongshu or both? isn't it bazi method is enough to tell everything?"
Yes, Bazi is enough to tell everything, which is why in Authentiic Date Selections, there is no need at all to use the Tong Shu! No matter for what purpose, not just wedding dates. For eg, if you move house or start reno and use a tong shu to choose this day, 90% you will be wrong, and worse still, if you reno on a wrong timing, there will be repercussions. The tong shu date did not factor in the occupants bazi as well as the house direction. Every yr, there are some directions that cannot be touched (ie not reno allowed). Eg for this yr, North is considered San Sha, very bad sector. If you reno without choosing a date (or just a tong shu date), and if you happen to reno on a wrong timing, over the next 4 months, you will get a least 3 bad things happening to you or your family. I've seen enough real life cases to tell you lots of stories about this. Many suffered from major health problems such as cancer or even death coz of this. Yes, it can be that powerful, so don't underestimate it.
For wedding dates, using the animal signs is just like using animal zodiac astrology to read a person's destiny. Very superficial only. To decipher a destiny, the birthday and time of birth has to be taken into consideration. For selectiong of wedding dates, tong shu date is not enough. Only by factor in the Bazi wlll you truly be able to tell if that day is specifically good for you or not. Without the bazi, and using just tong shu alone, is a very superficial way of date selection.
Hope this helps