Much like any other Chinese ARF, I'd just start out giving it 2 degrees down and 1 right, then seeing how it flies.

I do centering with a pen and ruler. Forget the existing hole and measure carefully.

As far as position forward, I get the engine mount in place then put the wings on the ARF's and adjust the C.G. as much as possible so that the engine stays for the most part within the cowl, but forward enough to help prevent the tail from being too heavy with the recommended or larger engine.

I'm in the same boat with a CMP Hellcat I just purchased from them.

Many other Chinese ARF's basically come with a single large sheet that looks somewhat like a blue print.

While the C.G. and throws are there, there is very little provided information.