Those are really all things you have to deal with no matter how you do it, as far as I can tell. Everything has tradeoffs. The way I do it now, I have to set the gain for each input on the AB switch on my tonebone. When I set that so the the keyboard sounds equal in loudness to the bass, FOH is happy (and he helps me listen). If I used the aux in on the genzler, I would change the ouput level on the keyboard, which would work pretty much the same as what I'm doing with the tonebone. If I sent the bass and keyboard to the sound board with separate DI's to different channels, I would be using an extra channel that we probably don't have, and I would lose control of muting or switching unless I add an extra piece of equipment in the loop, and more importantly I would have still have to find a way to get both back to my amp. In this case, it would be valuable to me (and slick) to get rid of a piece of equipment to simplify setup etc., but like I said, what I have works well (and in a couple other ways better), so no biggie.