Hello again diskus,
Well, I took some time and listened in to ZOA 35...and it turns out you were right. ZOA (Oakland Center, not NORCAL) simply tells westbound flights "radar service terminated, frequency change approved" and does not provide a frequency for ARINC. This happened three times in the short time I was listening. The pilots must already know what the ARINC frequency will be when they exit ZOA airspace.
And I also didn't hear any of the aircraft acknowledge ZOA's 'handoff' message so clearly they were already too far away to be heard by that feed radio. And needless to say, I also didn't hear anything on the ARINC frequency.
Ron