Friday’s reunion of Watchtower, a San Antonio-tied prog metal outfit with a rabid cult following, is sold out, but if you didn’t land tickets, don’t hang your head and cry. This week offers a wealth of other options for Alamo City music fans, from the sci-fi prog of Coheed & Cambria to the artsy vibes of High Heavens to the “anti-pop” of Drugstore Cowboy.