I purchased 'How to Raise a Working Puppy.' I want to build their drive; I'm concerned that the 'Drive & Focus' video won't help. What am I not doing? Or what should I be doing?

Why do you think Drive and Focus won't help? It's the video of choice to build prey drive.

If your pups are 6 months old and you are just now separating them it's very likely they have become way too bonded to each other. You can read about raising 2 puppies here. the whining is anxiety, because they are not used to being away from each other. This is not the ideal situation to have when wanting to train a working dog. We would have separated them at 8 weeks old and worked with them individually from that point on.

BUT, with all that said since you already have them then you need to use what works for each individual pup. If one likes food, then use food.
If they like toys, use toys. You can build drive for what they like and make it stronger.

I would read this article on Markers too. I use marker training for all my young dogs (and my adults too). We just completed a DVD on The Power of Training Dogs with Markers, it will be ready for shipment next week.

I am not a fan of letting young dogs watch bitework, I just don't think it accomplishes much. Back in the 80's and early 90's we did this but I have found that if the dog has the temperament and drive to do the work it's just not necessary and can actually scare a puppy, especially one that's not completely confident. I also don't want my young dog to watch a dog that's not a real strong individual because if something negative happens in training it may also set my puppy back in the confidence department.

Cindy