Glueball mentioned
The DC-8 Supersonic Flight
Thanks, well worth a read.
It seems to have been not entirely without incident.
Supersonic flight was achieved in a 20 degree dive.
"however the initial application of full up elevator did not appear to produce any noticeable change in the load factor"
They recovered by using the pitch trim. All moving tail trim? Reading between the lines I sort of guess that this was expected really - but still.
"A severe rudder pedal "buzz" was apparent ... from the oscillograph records ... The rudder control tab maximum movement was recorded as 21.3 degrees double amplitude, at a frequency of approximately 28 CPS."
Not sure what "double amplitude" means but it is still a large movement.