I've been looking at post hole diggers for my tractor. I'm specifically looking at a Cat 2 heavy duty auger. The choice is between the Land Pride PD35 and the Everything Attachments 7500HD. There's about a $500 difference in price favoring the EA brand. Also, what size bit should I consider for all things on the farm? Some say 9" and others say 12". I'll be installing fence 6" posts as well as possible some 6x6" posts.