My children will be in grades 1, 3 and 5 next year. It is obviously easier to teach all three children together. My question is, do you think it is possible to teach them together all the way through to Vol 3? When my eldest is due to do Vol 3, my youngest will still be in the age group for Vol 1 (Although he may start Vol 2 early). What do you suggest?
Expecting kids in grade 1 and 5 to manage and be content with the same lessons is a bit of stretch, but you are welcome to give it a try. I would start with volume I lessons. There are probably ideas/concepts there that your older s/d has missed or will need refreshed. In each lesson, you can ask your older to pursue the topic in more detail and depth, while your younger s/d still gets the basic idea. You may also have your older s/d help in gathering the materials for the lesson and in helping to explain or demonstrate the the idea or concept to your younger.
Whether this works or not will depend very much on the personalities of you kids. It is likely that your older will become impatient with the younger. All I can say is to give it a try. Please let me know how it goes.