Groundwork is the same for any breed or mix breed.
Except for lunging a gaited horse; they cannot turn as tight as a walk/trot horse. Their shoulders aren't built for that --- those shoulders are built for making long sweeping strides.
Clinton Anderson's expertise is in walk/trot horse industry and he needs to stay there. IMO, his new DVD is all about the money.
If you want to learn from the best regarding gaited horses, look at Liz Graves' web site. Liz Graves:Gaited Horse--Gathering the Gaits
Hope this helps:)