RE: Sig Kadet Senior Build
There is only one CORRECT position. It should be shown on the plans or in the instructions or both. Moving the engine thrustline randomly up or down is not a good thing to do. It will change the way it flies at least slightly.
Is there a detail drawing on the plans for the firewall and if so give us a close-up of it or the book instructions. Are there any marks (drawn or stamped) on the firewall that may be alignment marks?