So, I can cast a natal chart in any number of chart types. Specifically I'm speaking of Equal vs Placidus. 

If the Placidus tells me my sun is in the 9th, but the Equal says it's in the 8th, how do I know which fits? Aren't there some pretty standard X, Y and Z aspects that are typical of people with planets in their respective houses?

Do I have to read the meanings for all of them and decide which sounds the most like me, or something?

I know I sound pretty ignorant, but I'm not sure how you can decide which style to use if it changes pretty much an entire view what I'm working with regarding each planet in each house.  

luci, i think so--reading and seeing what fits. and you do not sound ignorant AT ALL, yo!

i dealt with the same thing when i switched to equal houses. everything except my 12th and 1st house planets moved over. 3rd became 4th, 4th became 5th, etc. it actually was pretty easy for me (easier than i thought) to make the switch in my mind when i thought about how long equal houses have been used for (since antiquity i think). it is somewhat recent (a year or two?) so sometimes old blog post comments come up and i'm interpreting from placidus. 

I sound like a punk in the way I word it, Kash. :D

But, seriously. If I read one house/planet description and go "Wow, that's not me at ALL" but the  house/planet description others seem to fit, that means I should use that vs the other?

It just seems weird how the types of chart completely screw with your entire base identity  

I'm a weird duck.  For some planets/houses Placidus seems more accurate, while for others Equal rocks my socks.  *lol*  I chalk this up to Sun-Neptune contacts and a stellium in Libra.  (Yanno: I can't see and I can't decide.  )