Rule of 3

Hi,
We are finishing Module 6 and are just beginning to implement TSG in our home (since Saturday). We have 4 children – 2 girls, 2 boys. Oldest, 16 has good self governing. We also have a 13 yr old with intellectual disability, 8 yr old boy and 6 yr old boy — all three need the 4 skills. We homeschool the 16 yr old and the two boys.
My question is about following through with loss of privileges during Rule of 3 when I have other children and meals to make, etc.
We've had lots of power struggles with our 8 yo son. Since we began on Saturday, he sometimes tries to come along with the program, but other times he is emotional, saying it's so hard. "Why do the books make it look so easy?"
On Monday afternoon, he was out of instructional control. I tried a modified Rule of 3 (15-20 min major maint; 1 SODAS; 3 HR loss of privilege). He was so upset about the 3 hour loss of privilege, refused to try to get calm and said he never would. He even calmly asked what would happen if he never became teachable/ready to follow instructions. Meanwhile I needed to make dinner, so I couldn't stay with him constantly to prevent him from playing or from going out and jumping on the trampoline.
My husband came home and I had to go out. My husband put him in a calm down spot again and again until he was ready to follow instructions and clean up all the messes he had made when he was trying to make me mad. (He was not successful in his efforts to make me mad – yay).
But he didn't do his extra chore or any of the Rule of 3 consequences last night because of the transfer between parents.
I listened again to the Rule of 3 video today so I'm feeling a little more confident to properly enforce it next time. Tomorrow I will tell him that I didn't properly follow the program and in the morning, when we are not in conflict, I will explain the Rule of 3 again and do some role play.
But what do I do if he just refuses to do anything? Do I set aside hours to chase him around and keep him from toys and playing outside? If he goes in the trampoline, I can't get him out unless I have another adult.
Thank you for reading! I appreciate your help.