...When you lay a cue from the side pocket to the middle diamond on the same end rail, you are forming an angle of 30°. When you lay a cue from the side pocket to the first diamond on the same end rail, you are forming an angle of 15°
I could be wrong, but pretty sure that's not true.
At first I thought he was off, but then I re-read and it seems correct to me.
*Standing at side pocket and looking at the Right Upper side of the table only*
1) cue line always originating from side pocket to upper right corner is 45 degrees
2) from here, pivot cue one diamond (move tip to the left)...this is a 15 degree shot
3) from there, pivot cue one more diamond to the left (middle diamond), should be the
30 degree angle