AD9833 clock sync

Hi All

I would like to sync 2 AD9833 together and just change the phase of one of them relative to the other in 1 Deg increments.

I see it is possible to use multiple AD9833 on one Arduino, but not sure if they are able to sync together like described for the AD9850/1.

Would I be able to use the onboard Nano 16Mhz clock for both AD9833 or is it better to use an external 25Mhz clock for both?

Kind Regards