Measure the depts of both reflectors on your originals before removing them and then put in the new ones as close as you can to that.
I forgot to do that the first time I swapped reflectors,
it just took a bit longer to get it right afterwards
Park on level ground on the centre stand facing a flat surface adjust the dipped beam to try and get the point of the angle up directly in front of each beam. Ensure both flat parts of the beam are the same height.
Put the bike behind a car, not and SUV, sit on it, the flat part of the beam should be just below the wing mirrors. If not adjust until it is and then take it for a spin to check if you think it is wrong redo it again or go back to your local MOT station and get them to do the final setting.