We all work and learn in different ways. I differ a bit from some of the other suggestions in this thread in that I think the group approach on your first pin is a great idea, partly because you can distribute the tasks to the people best suited to complete them, and also for moral support and group motivation. Yes, there will likely be conflicts and problems and all of the bad things that can happen in a group build, but if you're good at managing people and tasks and can get through those challenges, you'll all be thrilled at the result, or at least whoever wins the arguments will be.
Now that there are a lot of people who have completed custom builds and a lot more with builds in progress, there's a large community of like-minded people to support you. When you run into problems are simply want some advice, it's easy to find people to talk you through it. All that said, in my experience, the most successful custom machine builders are those who like to solve problems, learn new things, and dig in. If you're the type of person or you build a team with the type of people who are committed to getting stuff done (stubborn even), you'll likely find success. If instead your group seeks detailed and low-level help doing everything or most things, then you'll likely not enjoy the project.
- Gerry
http://www.multimorphic.com