We're not surprised that you do not like the audio coming from the setup you have.
The culprit is that awful, mid range prominent SM58 mic.
Allot of Stage Performers love this mic, and it is good for Live applications,
But we think the best application for this mic is on a snare drum, and used for a snare drum ONLY!
For Audiophile Voice applications, the frequency response is just not there.
In Audiophile applications, the SM58 is pure EVIL!!!
So the 2 decisions you made, to change the mic your using, and to get a parametric EQ, are very good ones.
The PR-40 is a great choice, so is the RE20, RE27, and a whole host of others depending on what you like.
We like the RE20, RE27 when used with an EQ over the PR40.
Be advised though, the RE20 requires allot of Preamp, you might even have to use both channels of the MIC2200 to get to the proper line level.
The RE27 has more output and doesn't have this problem, but it does have a rise in the upper mid to high frequencies for more clarity.
We like the flatness of the RE20, not to mention its low frequency Density.
As far as your choice on the FBQ2496 Parametric EQ,
It is a good choice other then one failing with that unit,
They did not include a memory storage capability in this unit to be able to store different EQ Filter curves.
This can become a real pain when you want to try different curves or use multiple rigs with the same rack.
Whatever Parametric EQ you decide on, you will discover that the adjustability far exceeds that of any Graphic EQ.
A Parametric is almost a must.
OK, Keep us informed of your progress!!
Take Care,