Stumbled across pianoforum by googling, and this was the first thing I came across.
All I can say is that attempting to learn works like Fantasie-Impromtu is pointless for most people, even those people who have been learning for many years. This music is not meant for people like breadboy -- at least, it isn't meant to be played by them. They have neither the deep knowledge, sensitivity, or humility to understand it, let alone play it.
Chopin (and Liszt, Beethoven and Schubert to name a few more) didn't write their great works in order of difficulty, or as a test of virility. They wrote them because they wanted to communicate an emotional truth or deep feeling, and the fact that they are difficult is because they have to be so. Piano playing is not a pissing contest. Being able to rattle out a bunch of notes in roughly the right order is not what Chopin had in mind when he wrote this music.
Having to ask the question "should I start it" or "how do I play 3 against 4" indicates nothing more than a level of ignorance that is entirely contemptible. It's like buying a Ferrari. If you have to ask how much it costs, you can't afford it. Likewise, if you have to ask how to play it, you can't play it.
I don't want to come across as too harsh as this is my first post, but, I mean - honestly!
A final thought - breadboy's audience, albeit consisting of family and friends, would probably appreciate a really beautifully interpreted - in other words, an honest performance - of something like "Traumerei", or even the Aria from the Goldberg Variations. However, this will almost certainly never happen as he will almost invariably want to slam them against the wall with huge chunks of notes from the "difficult" range.
If there's anything that will make your audience dislike you, breadboy, it's wasting their time by playing them things you can't play. The only emotions they will feel if you confront them with a butchered F.I. are a) embarrassment for you b) pity for you c) anger at your arrogance and d) a dislike of all things Chopin. If this is what you wish to achieve, then can I repeat what many others have said here: go for it.
God help you.