That Spelling Thing came about when classroom teachers started asking how they could deliver That Reading Thing. TRT will always be a one-to-one programme, but there's so much scope for subject teachers to use the same principles for spelling in almost any classroom.
The book is a training manual which will get you started creating a spelling culture in your classroom.
The workshops are online but live and interactive, giving the benefit of being able to talk about sounds and the spelling of sounds with sound!