Re-spraying engine bay

I painted the engine bay last August, but now I want to respray it. It has some runs and the metallics didn't lay down quite right. I also used single stage the first time and the rest of the car is going to be bc/cc.

I did prep it right. I sanded it down to bare metal and epoxy primered it and then put on 2 coats of single stage Acrylic Urethane on it.

How should I go about respraying it? Can I scuff it up with a red scotch brite or do I need something more aggressive? I know I will have to sand the runs out for sure.

I got the drivers side stripped down along with half the trunk. My goal is to have the body in epoxy by the end of April.

20180330_225016.jpg

20180405_204721.jpg

20180407_001246.jpg