>>> Personally I would be more concerned with proper incidence of the engine than the cowl and cone matching up perfect >>>

This is usually correct. The highly aerobatic planes like the Funtana series and others have right thrust and sometimes down thrust also built into the firewall. The engine should be mounted square to the firewall, nothing else. (if the firewall was installed correctly at the factory) Do you know why right thrust is needed?

Ernie