When designing a product using MatesBUS, typically a Breadboard Mates product would overhang and stick out beyond the outer edge of the mating board, however this does not strictly need to be adhered to, as Breadboard Mates products could be used in many applications and could easily clear other components on the designed board, depending on the height of the Female headers used.
Adaptors and Host products can feature one or multiple MatesBUS headers, and the spacing between these need to be considered based on the range of Breadboard Mates products that are wanting to be supported.
Breadboard Mates products are not limited for size/width, therefore consideration needs to be made to allow adequate/reasonable spacing between MatesBUS headers, or be willing to accept that larger devices may prevent multiple being able to be connected together.
The MatesBUS primarily uses a Serial UART for communication to a Breadboard Mates product, therefore if multiple compatible products are present on a Host or Adaptor, each must have access to an individual UART on the Host. For Hosts which only feature a single UART, either some sort of multiplexing hardware will be required, or limiting to a single MatesBUS device will be required.
Simplistic illustration of 2 MatesBUS products on an example Host PCB, connected to a single Host with 2 UART’s. The spacing between potential modules needs to be considered.