I think the best option would be to take the clock out and put the tach back where it ought to be. The original, available out of the junkyard, is nice and easy to see and I'd go with that one.

Most car radios now have a digital clock built into them. If you don't have an aftermarket stereo, I suggest getting one. Put a clock on the centre console if you must (find it in a junkyard)

You don't to see the clock while driving, knowing how late you're running doesn't get you there any faster. I trust you own a wristwatch.
--
Drive it like you hate it