Red
With the ladder attach points against the hull and cap, does it have to located in a certain area for them to be flush? The way the PII and Sabre are designed, it seems the cap attach points would only allow a very small area for them to fit flush. Also, it would have to center the air scoop on the top cap.
I would find where it best fits. Put masking tape down in that area. Use a pen or pencil to mark the attach point (circle), than mark center. I would do the hull first. Secure both lower hull points with the bolts, than mark the cap points. Remove and drill the cap points. Reattach it filling the bolt holes and contact points with Silicone. Only way I could see to do it without a template.
Don