Not sure if that is detailed enough for you but the screw spacing isn't super critical. You want the brackets at full extension to reach the thumb screw portion of the cabinet, and when the brackets are fully pressed in they don't extend past the edges of the head cabinet. If your screw placement allows for that much movement, you've got it right.
Spoon Tex, e-mail me. I will get that spacing for the thumb screw mountings in the speaker cab. With that info, you can find the points of attachment for the tie down slides.