In choosing a straight bit for any application, always select one with the shortest cutting edges and the shortest overall length that will reach the required depth. Excessive length intensifies deflection and vibration, which degrade cut quality and lead to tool breakage.
Use a two-flute bit where fine finish is paramount. Two flutes balance the bit, eliminating vibration that degrades the cut finish.
Two cuts per revolution yield a smooth surface, but feed rate is slightly reduced.