So, I had a Bartolini 2 band preamp installed in my corvette standard(bubinga). The tech informed me that the preamp came packaged with an additional harness for another 9v. He suggested to just stick with one 9v but offered to install the other one in the future if I wanted. When I got home I looked in the cavity and noticed that its real tight on space in there. Has anyone else fit 2 9v batteries in their corvette standard?