I would have thought that one of the dealer's might have stepped in by now and answered this? i.e. 'Will my digital back out-resolve the lens or will the lens out-resolve my digital back' is a pretty fundamental question for anyone planning to drop $9k on this bit of glass. For that price, the answer had better be the latter.
Given that the best-in-class Rodenstock 90mm HR/W is designed for digital backs of 5 microns and above (IQ180 = 5.2 microns), then I'm guessing this zoom lens is probably somewhere below that in terms of absolute resolving power across the frame. But by how much? There's not a lot of headroom, and if it can't resolve detail down to 5.2 microns then, well, that's a bit poor given that P1's top of the range digital backs are 5.2 microns.
Unless … this long awaited and expensive lens is intended for a future range of <=80MP full-frame CMOS digital backs? Kinda makes sense - I don't think we'll ever see another CCD back from P1, and even if an IQ180 out-resolves this lens, it's obviously still going to produce a very good image, just not the best one possible given the resolution of the IQ180 digital back. If you've invested $45k in an IQ180 and $9k in this lens, you've every right to expect the absolutely best image possible.
That said, even the IQ250 is a 5.3 micron back so again there's not much headroom for the performance of this lens to match the sensor.
Jim