RE: V tail setup?
A couple of notes.
Be careful of the range on your Sonic, the radio is only rated for 350 feet. That is very short range. You don't want to lose it. I launch my thermal gliders higher than that.
The wing loading on the Salto is about 16 oz/sq ft.. By thermal soaring standards that is a brick, But by slope soaring standards that should be a fast arobatic glider. But it will definatly need more wind than your Sonic.
At 50 to 60 degrees the hill is not very steep. I would think, based on your hill, you are going to need at least15 mph to keep it flying and 20-25 would probably be optimum. That is a total guess, but you are going to need a lot more than the Sonic.
Also, if your Salto was unstable, you may have the CGback a bit too far. Are you balaned according to the instructions?