There are some excellent threads on word clocks in this forum. I read all I could find; most advice to stay away from spending money on an external clock unless you want to sync multiple digital devices.
 
I'm looking into adding 8 IN/OUT via ADAT to the VS-700R. I reckon many of you guys do that already. Are you using the clock of the VS-700R, the clock of the other device (pls state which one), or an external one (which brand?).
 
I'd be interested in your practical advice as I'm already so full with theory that it comes spilling out of my ears again
 
Do you see any problems with having the second unit in a separate rack i.e. sending the clock signal down a 3m BNC cable?
 

It is important the moment you connect an extra unit that the clocks are synchronized. If they are not things will work but you may get some glitching and popping etc. 

The Word Clock IN on the VS700R is an input and a clock must be sent into the VS700R. It is not an output sending word clock. You don't necessarily need the word clock input to be used in order for clock signals to lock together. A separate word clock generator is also unnecessary.

If the extra unit is a two way ADAT connection to and from the VS700R then the VS700R can stay as master and the clock can be picked up by the external unit. (from the ADAT OUT on the VS700R.) The external unit will need to be set into slave mode. 

If the external unit is one way only ie into the VS700R then the VS700R may have to be set to slave to the external device. The clock is sent from the external unit via the ADAT lightpipe connection. (this is a less likely scenario)

A word clock generator could be used if you wanted improved stability. The clock coming from that is going to better than either of the other clocks. Then you would connect word clock leads from the generator word clock OUTS to the word clock INS on the external unit and the VS700R. (generator will have multiple word clock outputs) Both the VS700R and the external unit would have to be set into slave or external clock mode to both sync to the incoming word clocks.

I think this is all OK!

Make the V700R the master. It reverts to that setting every turn on. Use one ADAT cable, 2nd unit out to V700R in. Use one BNC, V700R out to 2nd unit in. Setting the 2nd unit may vary depending on what you get, but usually you will set it to the ADAT out you are using on it .