A new appropriate leader nearest the top could be selected then just let it grow to the height that you like. Myrtle grow quite rapidly when receiving direct sun. You can trim it to be double stacked instead of a regular single like you normally see.
Softwood or semi ripe cuttings aided with rooting hormone planted in a well drained mix during early summer is best time to propagate. Seeds also germinate readily. Good Luck!

Ankrara's Hobby Corner

I agree also, choose a new leader and tie it straight, to get
new height, I am a rookie too hee hee , I choose to take a cutting when I trim (can't waist it) dip in rooting hormone and
have a pot of construction sand in a pot (already watered well)
make a hole with a pencil end and stick it in there.
don't let it dry out put a bag or something over it or set it in a shady spot till it roots! Happy planting!!!!!
Cathy

hmm i too am a rookie, i dnt understand some of this terminology, but i too would like to make some myrtle cuttings could someone walk me through this please?