Hey Colin,
I've never heard of Bloodwood before, but from all the reading and research I've done, Teak is really the only way to go. There are some threads here that discuss different woods, why don't you check them out?
Regarding finding a place to learn. Try:
http://ic_spearguns.tripod.com/
Kitto has posted a ton of information for "Do it Yourselfers". You might also order a set of plans from Steve Alexander for 5$. They are very helpful in providing measurments etc. Other than that, scour the web for photos of guns, check out actual guns in dive shops or your buddy's house, and feel free to ask any questions you have here in this forum. I noticed that most people here are very williing to help lend a hand. I have just recently started building my own gun, and this forum here has been a great source of info and help.
Good Luck,
Lou
