Most modern nocks for aluminum or carbon arrows are adjustable, i,e., they twist into whatever position you want. Some nocks for aluminum arrows are glued on and are not adjustable. Just give them a good twist with your fingers and see if they move. If they are glued on and not adjustable, you are limited to nock height adjustments, as it would be too much hassle to break them loose and move them a little bit (if they will even break loose without heat), reglue, then test and repeat.