if you are cutting out VU meters, i would use biscuit jointer cutter. it has a small solid round blade... like the cross cut machines, but
tiny version of it... try on plywood first... count in the blade thickness ....
or make a mark with heavy duty stanley knife... do, 5-8 light passes... it will give you some depth... and it will be
easier to follow that grove with jigsaw.
dont forget to safety...
EDIT : do not rush