How do I get data from hundreds of ZB modules

hello there, I need your help.
There is about 200 meters to read in a Wireless Meter Reading system. I use 200 ZB end device modules(AT mode) with 80 ZB modules as routers. I divide the wireless network into 3 PANs, each PAN has about 100 nodes. And the coordinator is ConnectPort X2. All the nodes except the ConnectPort X2 are a battery energy sysytem, they can be waked up by RTC Alarm.
There are two methods to get the meters’ data:
1, the coordinator sends the command to each end node in proper order, and each end node will return a data to the coordinator. This process may take a long time and need more power energy.
2, End nodes send data to the coordinator automaticlly. This method may lose data if many end nodes send data at the same time.
My questions are:
1, Which method should I take?
2, How do I avoid the weak point?
Thank you.


How often would the 200 end devices need to transmit data? With a network this size, you might look at many-to-one and source routing in 2x41 ZB firmware.

once a day.
many-to-one and source routing is a good idea.
I found that only coordinator and router have the “AR” parameter in X-CTU software. Does it take significant effect Since there are only about 30 routers in a single PAN? Should I set the 200 end devieces into routers?
And with a network this size, what would the “AR” parameter be?
And should I update the firmware of the ConnectPort X2?
And which is more efficient the coordinator querying end node one by one or the end nodes sending data to the coordinator on their own.