Gunner has a sad, sad mane, so he already has a natural separation. Maybe as he gets healthier he'll grow some more there, but it may just be his natural look.
Hoover isn't ridden anymore, so I don't really see a reason to clip him, but I did when he was ridden. He has a fairly thick mane, so he needed it to help his bridle fit right.
"Sit tall in the saddle, hold your head up high. Keep your eyes fixed where the trail meets the sky. And live like you ain't afraid to die...don't be scared, jut enjoy the ride." - Chris LeDoux