Several good ideas already, so I'll just add a few.
1. First flight: have a buddy launch it for you so you can focus on just flying the beast. Once you see how it behaves you can launch it yourself.
2. If you get torque roll, you might consider taping a quarter or two to the opposite wing tip bottom. This was mentioned in a very recent copy of Model Avaition
3. You likely have a high wing loading, so watch your control setting. You don't want too much throw, and dial in expo
4. Try to stay in close until you are comfortable with the engine run. High wing loading planes tend to glide poorly, and an off airfield landing won't be pretty.

I fly Open B with 25FX and a mousse can, and I have some step ladder non skid on the fuselage sides just aft of the canopy. All I do is a light toss us to establish some forward and upward momentum and the 9x4 props scream hauls it aways and hauls it away

Good luck!
Ed