I have a Top Flite Cessna 182 ARF, and am getting ready to install the internal cabin parts. One part that is the first to install is the rear bulkhead in the assembled fuse. Problem I have is shaping the part to match the internal shape. I am experienced at creating templates to aid in matching shape, but I normally have access externally. I have been doing searches, but am not finding any process or tips to follow. Any help will be appreciated.