http://www.google.com/search?hl=en&s...om&btnG=Search
Read several of these threads. This is perhaps the most commonly asked question on Talkbass, second perhaps only to "maple vs. rosewood fretboard" (which I see you've already started a thread on as well).
But, if you decide not to read those, my answer to you is that, since you are asking these questions, you do not yet know enough about the instrument to make a neck, so you should definitely just buy a neck from Warmoth. Once you know more about what you want, you can try making something if you can't find what you want out there.