One of the problems is, you leave all the parts of the guitar on the template together. What you need to do is select the body/all the parts of the body. Invert the selection and hide all the other parts. Now select the body again and apply a mapping mode. The body template should stretch to cover all of the mapping area. Resize, rotate, move, whatever. When you're finished, save it as a texture template. Now unhide the other parts, select the one(s) you want and repeat the process for them. In the end, you can unhide all the parts. They will overlap each other on the texture template, but it doesn't matter anymore. Do not touch anything now, but save as a new model. Otherwise you will need to save new texture templates. Paint your textures on the templates, import the newly saved model into Bryce and apply the bitmpa textures in Parametric mode. It all should work now.

-- erlik