I give my dogs 200IU of Vitamin E every other day. You don't have to open the capsule and squeeze it out, just throw the capsule in with their food. Make sure it's natural Vitamin E and not synthetic. The label should say "d-alpha-tocopherol" and not "dl-alpha-tocopherol." The "L" is for loser, good way to remember.
As far as the young dog, I'd wait until he's a bit older before you start supplementing, especially if he doesn't have any health issues. I have a 6-month-old puppy and I do plan to switch him to a home cooked diet at some point, but not until he's at least 18 months old. I want to make sure his diet is properly balanced while he's growing.