Short answer: Yes. The procedures were necessary.
Even using them, it didn't take much to generate a noise fine (e.g. on a warm day, departing 31L from intersection KK because the full length wasn't available).
We couldn't climb ahead to 500ft like the blunties do because Concorde would be much further along the runway owing to higher take off speeds and a lower initial climb rate until you'd got above 250kts. We'd then be flying the turn at 250kts rather than the 160kts ish of a blunty so you have a much bigger radius of turn.
The solution was quite inventive and did the job well, taking advantage of Concorde's excellent handing qualities. And it was most enjoyable to fly, to boot.
I flew back from JFK last week and it just ain't the same.
