One way is to use ‘skid tines‘, which involve drilling three holes in the upturned portion of the skids with the same spacing as the two on the tines. This will allow you to mount the tine further down and increase its digging depth. Additionally, you can adjust the handles of your tiller so that it is only digging 2-3 inches deep into the soil. You can also re-pin the lift links to increase how far down your tiller digs. Finally, you can remove the tiller shoes for more depth when plowing and then tilling.