No, don't hit the wrappers/stripes until you only have 1 move left on the bombs or you absolutely have to. you don't want the clock to explode until it has produced the required amount of licorice. You need to keep eliminating the licorice by matching candies and making vertical striped candies or better still wrapped/striped candy combos. You should also eliminate one or two licorice every time you hit the wrapper/striped combo on the side.
I got it by also using a tick booster from the start, without it you will struggle to eliminate the required number of licorice without exploding the clock.