I have g12t-75s on my 4x12 Marshall cab and I think they "close" too much the Recto sound. When I record my Triple Rectifier using this cab I need to use a lot of mids and highs on my settings, turning down almost all the basses, but it still sounds too dark for a nice guitar sound. Maybe it's because this speakers (especially on Marshall cabs) were used with Marshall heads, that are very brillant in the sound. Instead speakers like V30, more "open", used with Recto amps, usually darker then Marshall ones, could be the right choose.