Crown Molding Install Question

Hi Everyone,
Thanks ahead of time....

I have a bit of a dilemma and my local homedepot is telling me conflicting things from what I am reading.

I am installing crown molding in a bedroom. Behind 3 walls are concrete cinder block and 1 wall has metal studs.

I decided to use backing block (triangle wedges) behind the crown molding with liquid nails.

So this may be a 2 sets of questions:

1. How should I be installing these backing blocks to each type of wall? I assume some liquid nails but what type of screw/nail for each type of wall.

2. Should I be going straight or at an angle (parallel to the block)?

3. When installing the crown molding what type of nails should i be using for each type of wall...?

Crown Molding Install Question