The angle depends on the placing and lift of the wing profile.
A high wing Clark-Y profile normally needs 2-4 degrees of down thrust.
A symmetrical mid wing don't need any up or down thrust at all.
Side thrust (right angle) depends on the moment and rotating air flow caused by the propeller.
Small high rev normally need less than bigger low revving props.
Only tests will give you the correct answer - but someone will probably have done the tests if it not your own design.