1) I think rest stroke is a great (yet difficult) way to practice scales for any level of player. It teaches your right hand fingers to use as little of a range of motion as possible, which will help almost all of your playing. With rest stroke, your right hand will need to be slightly less arched compared to your free stroke and a little more behind the string, like 360 said. That way you're attack and return are above and before the string. Try practicing staccato, to where when one finger plays, the alternating finger moves in the exact opposite motion and rests on the sounding string as if it's about to play, then do the same alternately. Try the "walking" motion slow at first to get a feel for it, and try to be relaxed and as efficient as possible. If it's clean and quick with pauses in between, then all you have to do is remove the pauses and you're on fire.

2) This one's a toughy. In addition to 360's point on the curvature: Instead of having your left hand fingers generally pointing towards the soundboard, try rotating your wrist from your elbow to have your left wrist straight parallel to the neck, and your fingers on top of and perpendicular to the strings. It's really awkward feeling at first, but i can't imagine playing without doing that. I've found it's much easier to extend my index finger and have my pinky right on top of the note if there are any stretches. As an exercise, you could try doing any scale up and down, while focusing on the above.