I'm building an small RC model basically from scratch using a set of CL plans as a starting point. My question is , how do I determine if/how much built in angle to the engine thrust is needed?

Specs:
.061 two stroke engine, 6x4 prop
length 23"
span 34"
mid wing, symetrical airfoil, no dihedral
tubular fuse, taildragger
240 sq in wing area
vert stab 15 sq in
horz stab 40 sq in (as plans, may cut down)
target weight 18oz.

Thanks Guys