I have decided to make another design change, but i did find a solution to a problem. The digital pots that i have chosen have a limitation. Maxim's DS3904U can't have more than .3v above V+ on the resistor or wiper of the chip. The initial solution was to use a simple voltage divider, like shown below.

The only problem is that would i would not have the full voltage range i wanted. The lowest voltage i would be able to achieve would have been six volts.

The solution was to use a voltage divider to divide the 30 volts down to 300 mV or so. Then use an op amp to bring up the v to about 3 volts. Then use that to drive the digital op amp. As shown below in the simulator.

In reality, it looked like this. I used pots since I know theory doesn't always become reality. That meter on the upper right shows the voltage going into the divider. 1st pot on the right was the voltage divider, and the other one was the feedback for the op amp. The op amp later drives that thumb wheel pot in the middle.

Unfortunately, i forgot to take scope snapshots of the circuit in action. However, the proof of concept did work. Yet, i noticed that near the ends of the pot, the change in the output voltage change dramatically. It did not act linearly.

I'll poke around to fix that later and take scope snapshots of it in action.