A table saw is fine for roughing your necks, I would imagine. I haven't done it myself, but it's been recommended to me by more experienced folks for my next build. Pick the right blade and you should be fine.
Regarding the scarf, I did have ONE setback when I did my first-ever scarf joint in my life for my neck:
- When you clamp stuff that's at an angle, there's a tendency for the pressure to want to 'squeeze' the wedge out. Making a good jig will eliminate this part of the equation.
- However, I did NOT use a good jig. Consequently, the part of the neck from the joint to the heel, on the fretboard side, was about 0.5mm higher than from the joint to the 'nut' area. Not good. People couldn't even tell, but *I* could tell and I knew it wasn't going to make for a good fretboard glue-up.
SO, I had to take a long, flat piece of MDF, put on some sandpaper with adhesive spray, and use good ol' elbow grease to level it all off. I worked the neck against the sandpaper rather than the sandpaper against the neck, because it somehow felt easier to keep the 'higher' surface consistently flat that way.
Greg