Ok, got 'er fixed.
Same springs...both of them. The way I figured, the spring holder on the carb had more leverage that the cable did where it was mounted. Moving the spring holder or springs was not an option, so I knew I couldn't move them down to where the throttle cable was. So, I decided to move the throttle cable to the spring mount where the huge half-inch hole is in the carb linkage.
I wanted to do this initially, but the throttle cable/pedal assembly wouldn't allow me to. I did some investigating and there was a small pressed on stop that was preventing me from being able to pull the cable out enough to attach it to the carb without opening the throttle blades and still have enough throw for wide open throttle. It was only about an eighth inch away from working, so I cut the stop off and it created enough slack to mount to the carb.
One other thing I noticed is how crappy the design is for the spring mount. Bolted together the way it is intended, there is about a sixteenth of an inch of play side to side, so the spring holder is really loose, which causes it to bind in the hole. The hole in the carb looks like it was pressed, so the outside of the hole is pretty course, which only adds to the binding force. My repair for this was to add some very thin shims to each side of the mount to take up the slack. The only shims I own were exactly what I needed, though I can't remember what the hell they were for originally. Cam button maybe.
After all of this I got in it with both springs pulled all the way back (heavy tension at rest) and pressed the pedal. That thing is so smooth now I couldn't believe it. It is as smooth as it was when the truck was TBI if not smoother. I had the wife come out so I could verify WOT and it seems to run out of throw exactly where it needs to. This should make it a lot more fun to drive.
Here is a picture of what I have now.