SRX

Just wondering if there's any official Juniper guidance on using JunOS as an NTP server for campus network environments ? 

I understand that NTP will need to hit the Routing Engine control plane and consume CPU cycles there in order to serve the requests, so just wondering is there any specifications on what amount of NTP traffic certain harware like a SRX1600 can handle ?

Which also raises another question of what the general clock stability is like for an SRX1600 to act as server, given that JunOS is effectively running inside a hypervisor on the hardware, is the NTP instance optimised any further for virtualised operation to minimise clock drift, or does it really not matter since it should be the only guest running on the hypervisor anyway ?

Hmmm ... I don't think the SRX was intended to be an NTP server. People say it works in general, but I don't think you'll find documentation for it. Besides, there are way too many variables -- your SRX1600 is not a dedicated NTP server, it's doing potentially a whole bunch of other tasks, so there's no telling how many NTP clients can sync time with it. In my opinion, best not to use it as an NTP server.