There is a series of DVD's called Masters of the Bare Bow. There are 4 of them out now. In I believe the second one is a section by Ken Beck of Black Widow on tuning which is a good intro. I recommend the whole series, especially if you're just getting started in trad.
You are drawing about 38#. You could probably get a 500 spine shaft to tune, but you would have to add a lot of weight up front, and you would end up with a really slow arrow. Some people like a lot of weight up front, and they might chime in, but I'm not one of them. If I were shooting your rig, I would shoot a 600 spine arrow with maybe a 75 or 100 grain tip, and start tuning from there.
I generally start my bare shaft tuning at about 5 yards, and tune until I can get good bare shaft flight out to at least 20 yards.