Wow...you might just laugh when you hear this.
I didn't realize until now that there is a "show digital display" option for a slider control under the properties menu. I can bypass all the rigmarole I had been trying...and just hook the slider control directly to the PID block.
Sorry about the hassle of all that! Nonetheless, I learned quite a bit in my roundabout process and everything works great now.
Can't thank you enough for taking the time to help me out,
-Adam