http://mmb.maverick.to/showthread.php?t=70006&highlight=custom+gauges&page=5 Here's what one guy did about custom gauges..
Nice looking layout, but I wouldn't weld it in. I'd have it secured by screws. You may want to access behind the cluster someday!
ive always been partial to the tach on the left and speedo on the right, but my cobalt ss was like this, so i guess you get used to it for racing purposes.
I like tach on the right. If you're shifting with you're right hand then your left hand is always on the wheel, partially obstructing the left side gauge pod.