Want to put and aftermarket tach in a rallye dash

Anybody here put an aftermarket tach in a rallye dash where the blanked off center hole is. I am concidering doing this in my sons rallye dash. I am keeping a vac gage in my rallye dash and using a shift light. I have seen the $240 aftermarket rallye dash tachs and heard they are junk.

What aftermarket tach did you use, and how did you mount it? I was concidering making a flat aluminum plate that screws in where the tach mounts, and drilling out its center to mount the gage into to it. I am looking for ideas, and pix with different tachometers used in this location.

Thanks
Matt