I stand corrected about CMYK, maybe I'm thinking about Leaf, or leaf V8 software which, IIRC, needed another $1500 piece of software for CMYK.
Regarding tethered shooting, two people came, one from Lastra, the UK importers and one, I guess from Sinar. They could not demo tethered shooting. Only shooting to the card or internal drive, plugging the firewire to transfer the files to computer and then viewing in CS. A very expensive card reader!. This was about 18 months ago, they said they were working on it so hopefully they have solved the issues now. Apart from that there were a few other issues that put me off like the Dalsa chip being, at that time, a stop too slow and the screen on the back was about the worst I'd seen. I repeat, 'at the time'. As we know all this stuff is a moving target and we can only make purchasing decisions on what we need and what we are offered 'at the time'.
Back to the P3. Yep, confirmed today by my dealer, no problem with the V mount back. Just costs a few $$$. While I was there I had another play with the Linhof. Decided that's not in the running. Although geared on all movements you needed to apply locks. Some of the knobs were too small. The gearing seamed almost to fine. If I wanted a sliding back, it gets in the way of the rise back knob (curable with some bendy extensions apparently), All to fiddley.
However, he did have an Arca F Line Metric with Micrometric Orbix there and I did take a shine to that. Some gearing, cross, rise and lens tilt which all seemed very smooth and fine enough. The swings were just friction but again very smooth, taught and seemed solid as a rock, even when just outside of the indent they didn't want to spring back in.
When the P+ backs are shipping I'll get a demo at the studio with the Arca. In the mean time, I'll have another play with my pals Monolith. I started this thread because the Ps are just second nature to me but I'm sure it wouldn't take long to get used to another system (I'm just lazy and want an easy life:-), plus with Sinar prices what they are I could save a few $$$.