A good concern ... and what I have found is: It depends on the steering wheel you have. Most modern steering wheels are smaller and thicker. They will obstruct your view.
I, too, intend to put my future tach in the dash in front of me as well. As much as I don't know exactly what direction I am going yet, I do know those pre-fabbed speaker plate replacements are not the route I will be going.
The only one I might have considered is
http://www.cip1.ca/ProductDetails.as...13%2D14%2D1001. It would mean one would have to use a 2-1/16" tach and some other gauge would have to go to the outside purgatory of obstructed view. It is still a case of last resort for me.
I suggest to do some measuring and see for yourself. You may find (or have) a steering wheel where you won't have that issue.