Doomsday,
If you're only wanting nothing but volume boost for your solo channel, you might consider something as cheap n' easy as putting a graphic EQ in the loop, flatlining the sliders, and boosting the output slider to the desired level of volume increase.
However, if you're planning on doing much soloing, you might keep in mind that Rectos, while monsters for rhythm, aren't really known for their sustain or their singing, harmonically-rich mids. IOW, it's possible that your solos will be louder with just a boost, but still a bit anemic in terms of tone. If you want to add back in some vital mids and harmonics as well as just making the solo signal louder, you might consider what jdurso already wrote about.