Just give it a try

your micro idea never occurred to me, so I like that you are thinking outside of the box. However, this is something you can easily test, so that would be my preferred solution: Rather than a discussion on the topic, which might not produce useful results for you, why not give it a go and if you happen to micro better this way then all the better.
One problem I can see with this is that you have to rearrange your control groups once units within that control group die.
All the best,