Some good info from JupiterAsc... and yes of course, the more precise, the better.
I have a question, tho --- JA, maybe you can answer this. MJ82 has Uranus at the same degree as her Midheaven, and in modern astrology, Uranus rules her Ascendant. So an event timed to 4 Sagittarius could be Uranus-related and important, rather than MC-related. Could be either instead of both, depending on true Ascendant degree, and even if the birth time is tweaked, Uranus and her MC are probably close enough to be conjunct. How do you distinguish?
MC82, you said "I don't even know how fast or slow certain planets transit to be able to tell if something was accurate or not." Check downloadable ephemeris files at Astrodienst.com, or buy the Ephemerides book. Hugely useful!
Just my two cents' worth below:
Events can be messy. Some planets (could be Uranus in your case) might well activate events while applying a degree or so to an exact conjunction (or square or opposition). When I moved, it took almost five months from the time I decided to look for a new house and contacted an agent about it, to the time we moved in. There are often contingencies that make an 'event' into a 'process'. In a situation that rolls on for months, I'd look at more than the culmination date, and different planets are likely to be involved in various phases. Another example would be parental separation prior to a divorce; both would certainly impact a child, who may not understand the legal differences... just "Mom and Dad aren't together any more".
Events with a quick onset, such as starting a new job, the first time you met your lover, or an accident, are easier to use, because you can identify the timing pretty precisely.... though I wouldn't change jobs or get into an accident just to time it.
