I don't know where you think you looked it up but 22350 VC does NOT indicate any specific speed over the posted limit. It is here:
22350. No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or property.
There's nothing that precludes radar from charging it either. There's nothing in radar or the road that mandates 22349. 22349 are default maximum speeds that apply when there is no posted speed. The limits in 22349 apply UNIVERSALLY regardless of conditions, traffic, etc... 22350 is open for argument as to whether you what the safe speed was relative to what you were observed doing.
There are no technicalities that void things just because of what is written on the ticket. Also, the speed trap law doesn't apply here.
The courtesy letter means SQUAT.
The limit is 45 days from the time the charges are filed until trial unless you waive time or do something that delays it.