Alan, first of all, a big welcome to a great bunch of people, also known as the family!
You will see by a lot of MOCers signatures there is a lot of short bed trucks. I have been pulling a Montana since 2001 with a s/b truck and a manual slider hitch. Although I have never had a problem(knock on wood!) with the manual, I would suggest the auto slider, why take the chance if you don't have to!