I'm looking to pick up a second mini skid steer to work on our new irrigaiton crew next year. This will be our first year with irrigation so I'm completely new to the game. We have planned to concentrate on residential installs and small commercial jobs. As I'm looking at trenchers to buy I see there are all different sizes and types. What size do most use for this type of work - how deep do the irrigation trenches need to go? We are located in the southeast missouri, northwest tennessee, west kentucky area. Also I'm looking at a mini skid steer to tug the trencher around. Will a 20 horse gas engine be big enough - like on a Bobcat MT50 or Dingo 420... Or would it be smart to go bigger and diesel to complete these tasks. Do most trench and then hard pipe in pvc or are you ripping and installing a flexible pipe? Thanks for the help.