Carefully.....

CG {if the foreplane (Rafael is a canard fighter if I remember) is over 5 inch average chord} will be at a point determined by "balancing" the area of the foreplane wiht the area of the mainplane, using 27% MAC as the locations of the "weights"

You will find ths discussed many times....

If the average chord of the forplane is smaller... you essentially ignore its presence and then balance at appx 15% to 17% MAC of the mainplane. (just a bit ahead of normal for a flying wing)

Airfoil selection is a matter of determining:
A) how close to scale do you want it to appear
B) how do you want it to perform
C) which is more important... A or B?

A scale airfoil will be thin and at model scale... essentially a streamlined flat plate. (inefficient at making lift... its partly a matter of never getting near sonic speeds...)
The thicker airfoil that works better at R/C model airspeeds may just plain look wrong.

You'll probably end up using a symetrical airfoil that is a compromise between effciency and scale-like appearance (a thinned variation on one that is commonly used in Pattern aerobatics models for example)

Make a mock-up of your final design from blue styro insulation... weight it to ballance and see how it glides. You can learn a lot very cheaply that way. When it glides well... add 3 channel electric prop drive... (why waste the model?)