Hello there,
I am not the best one to reply to this but most 'bad' transits (at least the ones that really bother me/are noticeable) are the ones from the outer planets, since they move slow and stay in a place for a really long time.
Like Saturn, Uranus, Neptunus, Pluto (not in that order). (Transits with these planets do not all have to be bad necessarily.)
I am unsure about the faster moving planets, but it can be that they can set off events, especially if predicted in a (solar) return. (Could use more experience in reading returns too.)
Look at what is written about transits on Azazels astrology in the witchcraft section on the main website. Link to the page should be at the bottom with/around the synastry.
Do take into account any minor aspects as well that said planets (first alinea) might make. The effects might not be as noticeable as when they'd be in hard aspect or a transit, but they do have some influence.
If there is something not in Azazels astrology and it makes an aspect, do some searching around on the web..
Also, you might want to do a forum search, like in the astrology section.
I am sure you'll dig up more information that way
If anyone else has anything to add, feel free to do so.
~Lunar