I have to agree w/ Judy on the training..We joined our local AKC club this year and I'm so thrilled we did. We drive 40 minutes to go there and in my opinion worth every minute. Plus a kennel club offers so much more than training!
I wouldn't see a problem giving him a large kong if you can't find the small or medium ..hey it will just keep him busy longer
I would go w/ the medium if you can find it..the smalls are really really tiny.. Also get a few of them if you can..makes life easier. I usually stuff a few of them and toss em in the freezer. I usually toss mine in the dishwasher to clean them.
It sounds like you are taking the right steps towards raising a wonderful dog!