The W-Modbus product does not utilize any leaf nodes, all nodes connected to a slave/server device run in mesh mode, while the node connected to the master/client acts as the network root.
MiraMesh is designed for robustness and power efficiency in difficult radio environments, which comes with a natural cost to throughput and latency. While throughput limitations has negligible impact on Modbus, the latency might.
As a general rule, allow ca 60 ms of latency per network jump from the root node in Round Trip Time (RTT). For example, a node that is 3 jumps away may introduce a latency of 180 ms, compared to a cabled solution. This may have to be considered when configuring timeout parameters on a Modbus master/client.
A general recommendation is to set any timeout parameter on a master/client to at least one second.