What R, C values to use in an RC Snubber to reduce output ringing in switching regulator?
As far as snubbers go...

If you want to absorb as much noise power as possible then C in the snubber should be large enough that its impedance is near 0 and much smaller than R at the frequency of interest.  R should be matched to the noise source impedance if you want to absorb the maximum amount of power from that source.

1/(2 * pi * 185MHz * 120pF) = 7.17 ohms.

So your 7 ohm resistor is about optimal.  The only improvement you may be able to make to the snubber is to increase the 270pF capacitor.  But be careful that the resonance frequency of the new capacitor is several times larger than your 185MHz noise frequency.

In general...

800mV of ripple does seem excessive in my opinion.  If you have enough capacitance on the output of the regulator you shouldn't be seeing that much ripple to begin with.  I would try adding more ceramic capacitors on the output of the regulator.

If that is insufficient, then a low pass filter consisting of a 10nH inductor, 10uF capacitor, and 63mOhm resistor would form a second order low pass filter with a cutoff of 3.16MHz.  This should essentially eliminate all your noise at 185MHz.  When designing the filter be sure that R > SQRT(4*L/C) to prevent ringing, and be sure that C has a high enough working frequency (or use multiple capacitors in parallel to get what you need).