Sorry, sags -

I just noticed this question. 

The FD in the real 707 was nothing to write home about. It worked, but few of us liked it. The one I flew was different from the one in the CS model.

The FD in the CS-707 does not do much at all. I believe CS is working on a few 707 bugs and maybe it will work soon.

As for the climb... at heavy weights the plane would sort of peter out around FL300.
I could kick myself for dumping all my old books so I am not able to give you any real data.
We always used EPR, with N1 as a back-up but I can't tell if the CS numbers are any good.

Best I can remember with the 707-300B or BA was a lot of step climbing as fuel was burned off. The -300BAH had slightly higher thrust engines and did a bit better.

Sorry again for the long delay.

Lou