1) I installed a small splitter in the airflow to split the air into the exit holes. I guess I could have just eliminated the center structure blocking the flow but I thought it may need to be there for strength.
2) I opened up the exit holes all the way to the edge of the heat duct providing a smooth transition outlet for the air. Now there is a nice unobstructed flow to warm the tootsies.
Now on to skin the interior fuselage bottom...cab