The Thunder Tiger Stik 40 is an aerobatic model. As such I'm expecting that you'll be putting the CG at a suitably aerobatic location. That means the CG will be located fairly far back and close to the neutral point. With that in mind you should need little to no downthrust and at most only a degree or two of right thrust to sort of compensate for the power up front. At most I would suggest 1 degree of downthrust but really it should be zero.

Set the CG via a series of dive tests such that it has little or no tendency to pull up and not a hint of tendency to tuck to a steeper angle. Then if you find that the model is nosing up strongly when it speeds up due to diving or adding power only then shift it to one or two degrees of downthrust. But it's likely you won't need to add any at all.

Downthrust is a bandaid added to compensate for a strong positive pitch stability. Trainers run with a high degree of positive pitch stability so they need lots of downthrust. Pattern models with their razor edge design and trim need no down or right thrust. The rest are somewhere in between depending on how close they are to one extreme or the other. Your Tiger is closer to the pattern model.