Why all the fuss?
I'd read it all back, not worry if I said more than I should, and get on with flying the aeroplane. What harm can it do? Even on a VERY congested frequency? Grab a stopwatch and see how many extra split-seconds of transmit are saved by reading back all, or half of this instruction.
This is not a smart arse response, but an honest answer to the question "what would you read back?" I really am interested to know if the controller and myself are on the same channel (so to speak). This is, after all, the purpose of a read-back.
BTW, I think this is a bit of an extreme example (but makes the point well). I don't think I've ever received a control instruction that long...
Triadic,
What would you readback? You seem to know a fair bit on this, and "I say again" I am not being a smart arse but am interested in the answer.
CR.