@timwoj,

I do not think you have anything to worry about, the devices were already designed to be used in a tight environment. Most wall switches are pretty crowded when it comes to the space and wires behind them. The biggest concern when there are a lot of connections in a gang box is that a wire could come dislodged and bridge a connection between them, For this reason, it is extremely important that you connect all the wires securely, as it could be knocked lose by all the extras in the box.