Tristan, what everyone's trying to say is that it's hard to give you answers you'll really understand given your current level of knowledge
With all due respect, I think that what everyone's trying to say is, "The questions you are asking are not going to help you achieve your goal at this time. Here are the questions you should be asking."
Tristan: as an example, you are asking whether it's better to take route X or route Y on a journey that may or may not happen 4-5 years from now. The fact that X=the Canal and Y=the Horn isn't really the problem (though it probably encourages everybody's blood pressure to go up a bit). Like Jeff said, your focus is wrong: you don't start planning a route for a trip like this when you haven't figured out what sort of a boat you need yet, or how to use it.
All the advice you've been getting is good, and fairly complete, so I will just say that where I think you should focus (and where I would focus if I were just starting out) is the OPB suggestion. Follow that and you will discover what it is you want in a bigger boat and what sort of sailing you enjoy most. Then get yourself such a boat and plan such a sailing trip, then you can come back and ask for help with route planning, though by then you will have discovered that it's probably easier to go east around anyway.
( It's beginning to look like Tristan is a troll . )
So far I disagree... trolls don't usually claim to be planning on taking ASA courses, do they?