What is the appropriate peck amount?

Pecking is the process of periodically allowing your drill bit or end mill to lift or retreat when making a hole. The purpose of pecking is to make sure that the chips are coming out of the hole and that coolant/lubricant is going in. As long as these two things are happening, you do not need to increase the amount you are pecking. If chips are coming out, then pecking is not necessary. If your surface speed is correct, then most of the heat created during the shearing of material should leave in the chips, reducing the need for coolant.