We would like to demo a Cat 302 or a 301 for irrigation install work on the next big job we do. We usually trench, but sometimes in real rocky soil using a mini is much better. I've finally talked my boss into trying a demo unit out We've never done a demo before though, whats the usual proccess? Also, the majority of the work will be trenching with a 12" bucket about 14" down. Perhaps a 18" bucket when working with real large pipe (3"-4"). I'd also like to perhaps attach a trencher or vibratory plow to the boom, is this easily done? What size Cat would you reccomend?