Hey, that's where I put mine, too ! It's a popular place for an extra switch... Easy to reach, plenty of room and wires going through the firewall happily end just there.
At the beginning I wanted to install it in the "right" place for a fog light switch (leftmost part of the dash, on the left of the HL switch) but then I remembered the trouble I had when replacing the instrument cluster and gave up.
Following a friend's suggestion, I installed an underhood relay for the foglights, as well as a fuse from batt. to relay, so that I need only one low gauge wire from the switch to the relay under the hood. The heavy gauge wire run is limited to the battery -> fuse -> relay -> lights circuit.
The current to "wake up" the relay is routed through the switch from the feed of the rally pack gauges illumination, so the fog lights will come on only if (at least) the markers are on.