Tim, the fillets look fantastic! I'm sure they're a lot stronger than balsa, too. I have to be careful handling the SK so I don't chip them.

It's not too late to side mount the engine. Remember, there's no need for any kind of structural strength forward of the firewall; cowls are just for streamlining. It would take you about an hour to change and you'll be glad you did for the life of the plane.

David