Need to countersink holes in CF, which bit do I need?

[simplechamp]

Do I need a certain angle or anything? Or are metric flatheads a standard angle on the head?

EDIT: Wikipedia says "Countersink cutters are manufactured with six common angles, which are 60°, 82°, 90°, 100°, 110°, or 120°, with the two most common of those being 82° and 90°. Countersunk-head screws that follow the Unified Thread Standard very often have an 82° angle, and screws that follow the ISO standard very often have a 90° angle."

So which do I need?