Get stats for # of calls wait in VQ in real time split by time ranges

Using Platform SDK in an 8.1 environment I want to be able to get the following statistics in real-time:

Number of calls in waiting for a specific VQ for the time ranges:
0-30 secs
30-60 secs
60secs +

There could be a large number of clients querying the stat server for these stats. Can anybody suggest an efficient way to do this? I’m new to stats in Genesys. I’m thinking this can maybe be done with creating a custom statistic or something but I’m not sure.

You need just standard statistics, custom is not necessary in this case. All parameters for that stats you have to fill in creating Request via PDSK (time-ranges, object, stat type, etc.)
Large number of clients is not problem related to your code in PSDK but to badly deployment/using.