RaZberry / OZW Good Practice Setup?

[khavusr]

Been running for quite a while with Domoticz together with RaZberry board but while it works kind without bigger issues, except when a node seem to give one some trouble, which by the end of the day ends up with only one recommendation - Factory Reset of the RaZberry board... Since I might get to the end of the road for such activity myself (currently have the annoying message: Not all Nodes have been Queried yet, OpenZWave not fully initialized yet!). I was wondering about what is really good practice setup for the RaZberry and OZW?

For example quite often it's mentioned that device polling should be avoided if possible and if used the value should be increased. Disable the polling typically doesn't provide any problem, just that a few Qubino's on my side might turn red if they haven't been utilised for a while. Enabling will increase the zwave mesh network traffic and therefor the polling value should be increased. I've set it to 60s and I have 15 devices. Any recommendation here based on the number of zwave devices vs poll time?

Another parameters which seems essential to make use of is the, security network key, but on the other hand, quite often it's recommended not to use it as it might cause more issues than benefit when it comes to OZW. Whats the general saying here?

Any other suggestion which of course might be different based on whether one have 5,10,20,30 or more devices?