On the CAP-- NO downthrust is best - The model has "effective" downthrust aplenty.
put in some right tho - not critical say - 1/2" total difference in prop tips measured from vertical fin to each prop tip when prop is horizontal .
This is NOT critical -just insures you have right -not left thrust.
These models run heavy so you may experience it tucking on vertical extended climb.
This is due to speed bleed off .
Don't bother screwing with thrust line to correct this.