ILR form for above 18 year old

My spouse is a British national and we are due for ILR in the coming months.As a spouse,I will be using the SETm form with one of our dependent child who is below 18.But we will also be applying ILR for our son who is 20 now and entered UK with me when he was 15.We know that a separate application has to be used for him.But should we use the SETm or SETo form for him.Kindly advice.

If your son was part of your application before don't do a separate application for him put him in your application with your other child that is below 18. They are going to grant you all together as a family.

Agree.