The multimeter I'm using is a Radio Shack unit that is true rms. However the duty cycle function isn't cycling, so that's why I'm using voltage. I can convert that to a 6.8 - 7.4 V as the 45 - 50% ideal range.

The stand differential pressure I've seen referenced for the bosch system is 5 bar in the upper chamber and 5.5 bar in the lower chamber. It was reading 6 over 6.5. From what I understand that won't have a huge difference on the operation of the vehicle. It just verifies that there are no restrictions in the fuel system

So what do I make of the momentary no signal at 1500 RPM? It seems like the CIS is getting an implausible signal and cycling.

1986 & later MB CIS-E systems operate at higher pressures than "stand".
The readings of 6 bar (upper), and 6.5 bar (lower) were correct. Low pressures result in leanness.

Re: implausible signal
Have you verified O2 sensor voltage?

Before going any further with the fuel system, it may be helpful to run compression pressure, and leakdown tests.