Right. let's start from the beginning. First, take a copy of the original texture folder to back it up. The quickest method is to use the right-click options. Right-click on the Texture folder & select Copy. Now right-click in a clear space & select Paste. You will now have a new folder named Copy of Texture.
Open a texture from the Texture folder in ConvR8. Send it to your graphics editor by double-clicking the large image. Convert the color depth to 16 million colors. Resize it if necessary. Repaint as desired & exit the graphics editor. Click Yes when prompted to save changes. Click on the image in ConvR8 to load the repainted texture. Click File/Save as R8 & save the file under its original name. Make sure you use the correct file extension when saving. Now go & check it out in the sim. If this worked try the next texture & so on. Take this in easy stages. Don't try to do it all at once.

PS. If all your Sea Furies are the same model you have a texture conflict. Concentrate on repainting this one for now. We can fix that later.