You still have the problem of no pitch lever arm - you can rely on the cockpit reaction wheels somewhat ( from the look of the craft you're currently relying on them completely ) but that only lasts as long as you have electric power, so it's generally always best to seek an aerodynamic solution. I use FAR so things are slightly different, but I'd recommend something like this - notice how far the elevons are from CoL.
For some reason the CoL ball didn't show up at all, but it's about 1/3d forwards of the rear of the centre tank, so roughly where it is in your shot too.
As a side note I just put that into orbit using a single large SRB
