I currently have a Pignose G40v amp that I'm going to put into a empty Fender Champ 12 cabinet. This way I can use a 12" Jensen Alnico that I have for this amp. My question to all the experienced builders here is that the open panel for the Fender cab is about 15 1/2" while the G40v is 12". What should I use to attach the Pignose to the Fender cab amp straps and what can I do to make up for the difference in size. Thanks in advance.