I recently inherited a Mesa 400+ amp and am a little confused as to what output I should be using to send to the cab, the 4 ohm output or the 8 ohm output. The cab is a Mesa cab, but I don't know what model, and there aren't any indicators in the back as to impedence or anything of the sort, just one input in the cab's road case. I've included a pic b/c it looks like it's possibly a custom cab? there's a 15, a 10, two 6's and a horn. Any help as to how I should run it would be great! Also, as a side note, There's a lot of sticky, deteriorated foam in the case for the head. I've cleaned most of it out, should I find a piece of replacement foam to put in the case? Thanks.