I'm wondering if anyone has advice for hole preparation for the CS4-4 pop rivets used on the aileron bottom skins. Do you dimple for a -3 rivet then drill out to 1/8th inch? Or do you dimple for a -4 rivet from the start. I've worked with some practice material using both methods and they both seem to work OK, but I worry about a larger dimple on the aileron spar. Thanks in advance for any advice.