ZWave Network Design

Can anyone provide references for best practice for network design of a ZWave network as well as placement of the Vera for optimal performance?

My network has 12 devices currently including an HSM100 detector and 2 remote controls (HA09 and HA07). My house is about 5,000 sq ft and I have Vera located in an upper floor bedroom that I use as an office. I have 2 modules located outdoors for controlling the landscape lighting. I have intermittent issues with polling of the outdoor modules and slow response from one of them consistently. Also the HSM100 does not seem to work consistently even if I move it indoors and rebuild the network for its new location.

Any tips on improving the network/mesh robustness, or guidelines would be appreciated. Does anyone manually build the network by setting the neighbors, or does everyone let Vera do this?

I thought that placement of the Vera device would not be important as this should operate as a mesh network, but possibly I need to optimize Vera’s location.

The biggest problem is distance and signal blocking.
indoors 25’ would be a max through most drywall construction. Remember Battery devices are not repeaters.
Vera optimally woud be closest to the middle or the most devices. I would not place vera at the end of the chain.