Using a 3rd party flash with high shutter speed?

I have a Nikon SB800dx on a D7000 and I also have a YN560 which I want to use as part of a multiflash setup.

I've not done much CLS at all, so I'm not sure if I can getaway with using the YN560 with a shutter speed higher than the 1/320 sec in auto fp mode.

I will only be using it for delicate fill in light with a balanced background with shutter speeds between 1/320 and 1/750.

Will I get noticeable banding? I may need to experiment.

Most cameras that I know of have a sync speed of 1/200. I have one Fuji that goes to 1/1000 but these are rare,

If you have a camera that will go higher than 1/200 then go for it.

I don't know exactly what kind of work you're talking about but I use a multi-flash setup often. Mine externals are light triggered and do a very nice job of filling the scene.

The D7000 maxes out at 1/320 sec for its flash sync, so going beyond that guarantees more and more banding.
http://www.kenrockwell.com/.../d7000.htm

But, apparently there are ways to cheat on this that I haven't tried.
http://strobist.blogspot.com/2011/03/nikons-d7000-sync-dial-goes-to-eleven.html

In FP Sync mode or Auto FP, most Nikon cameras can go to 1/4000th of a second shutter speed (and the D7000 can go to 1/8000). However, it requires a compatible Nikon speedlight to do so.

The way FP Sync works, if you don't know, is that while the shutter speed is high, the flash duration is extended so that you do not get that familiar black bar across the photo at high shutter speeds. This of course means the flash will heat up rather quickly, so it is not for repetitive shooting.

But you need a Nikon Speedlight that is FP Sync compatible. I would doubt the YN560 would have this capability, but you never know.