I made some tests using the final component values for our FAB1248 DC/DC converter.
Using a 12Volts DC input, phantom power voltage output remained constant at 47.90Volts, up to 47.84Volts at various loads and current draw.
For example, at 57mA current load, voltage output measured is 47.87Volts, with 152mV ripple according to our oscilloscope. This translates to about 0.31% ripple! Ripple frequency has a period of 6.07us, or 164.7khz.