The attached picture should help. You want the engine angled down 2-3* in your case. The bottom side view shows bulkhead #1 mounted vertically and the engine angled down from that point. The upper top view shows the engine mounts angled to the right. Picture that as a side view and the engine would be angled up. You would want the opposite with engine angled down. Hope this is clear. I measure the angle at the firewall. Measuring from the spinner as you have it, the engine would sit higher in the cowl area and may not fit properly. If the plan shows a thrust line thru the firewall, I would measure there. Just the way I would do it.