Chilli Monster
Thank you for confirming what I thought, and my apologies to those instructors who told me what I said
Mind you I still have to deal with the CFI (ATPL) who told me you can saturate a VOR (a
VOR, not a DME) if you tune too many receivers to it...
I would transit to IFR as the zone boundary i.e. pretty well right away. But one won't get an RIS if below the minimum authorised RIS level for that radar unit, so in the conditions described one would be IMC by the time one gets any cover.
Except for the engine failure scenario (which assuming one can actually fly in IMC is statistically the only real risk) I would be quite happy to depart in those conditions - IF the destination and alternate are both clear.
What I don't know is whether the PILOT himself is able to phone the radar unit before departure, and get a squawk allocated.