Hi Phani,
I have discussed this with the team and the consensus is that this is difficult to estimate. However, it is the same as if you were managing a device that was not modeled using an SDC. There is no real way to determine how much data will traverse between Spectrum and a device it manages. It is all relative to the type of device.
For example, a device that has 2 interfaces is going to have a lot less traffic to manage it than a device with 100 interfaces.
When a discovery is run, Spectrum sends out a lot less traffic to a work station device than it does for a core switch device.
It also depends on the polling interval, Trap rates, and reconfigurations. It would be very difficult to estimate. Especially for traps.
I hope this helps.
Regards,
Roger