I agree with Mike's comments.
I used to have a Skylark and flew it on an OS 45FSR which was ample for it.
I flew that plane for 100s of flights and finally retired it because of some fluel soaking in the balsa all over the engine area.

This was one of the best flying planes of it's era.
From memory, the thrust was set for 2-2, that is 2 degrees down and 2 right.
Start with CG at the spar (most Goldberg designs were like that) and you will be fine.

Happy flying