Your range of 12-16A for a small hole is very large. You may not be able to achieve that intensity unless you have a large lance. What size media are you using? What air pressure are you using? Your procedure so far is correct regarding the strips since you peened the shaded strip with the regular nozzle and then peened the shaded strip with the lance nozzle trying to get the same arc height.
Are you sure that this intenistiy is required inside the hole?
