That's the exact combo I have in mine. It weighed in at 6.5 lbs.

For entry air I have the cowl opening in front of the head (right side of plane), and there's about 3/16" gap around the spinner. I had to carve a lot of the cowl in order to get it over the muffler, so there's a large exit area. I am hesitant to cut the left cowl opening since I'd rather force the air over the head, but I was thinking of opening the small scoop below the spinner. What did you do?