I know the ISD falls somewhere between 900-1200m, Though compared to the Tantive IV at the start of EP IV being just under a quarter of the length I have to wonder about the length. I doubt we'll know in a cannon sense simply because anything that could tell us from a cannon standpoint is no longer cannon including the incredible cross sections and the SW technical manuals.

I'd be happy with 1.2 though, it is a big ship