I'm not an expert on telescope mounting, just a silly engineer, but if
I were to build something like this, I would NOT mount it in the
manner you describe (slightly raised and using steel bolts to both
hold the pier and to level it). I would mount it directly to the most
solid surface I could.

I've got several reasons for that. Steel is "springier" than
concrete. You should get more vibration the way you describe. Also,
the coeffecient of expansion of concrete is essentially zero. Steel
will expand/contract with temprature. What that means to you is that
your degree of "level" will change if the adjustment on all of the
bolts isn't exactly the same. The amount that this will change the
level may be outside of your tolerance for caring about, but it does
tend to negate what you are trying to accomplish.

Finally, since you are making a permanant mounting system, I would try
very hard to dispense with the wedge altogether, probably by trying to
design a head for the pier that would already be in the correct
position for polar alignment.

Just my thoughts.