Factory Tachometer Size

I was recently considering installing a tach in my '65 barracuda with the hopes of finding an old factory tach from a Formula S model.

After some searching, I found that they are almost impossible to come by and the ones I did find were being sold in the $400+ range. I did however find a decal kit to use in conjunction with a standard tachometer for around $10.

I figured I could buy the kit and any tach and just make a mock Formula S tachometer. What I can't seem to find though are the dimensions for the Formula S model. Would someone happen to have those and if so, be willing to share them?

Thanks!

The actual round tach face is approx 3 5/8" and the whole assembly with the bezel is close to 5" square.