Pie Man;
We normally have upwards of 20 to 25 aircraft on freq when busy. Sometimes have had up to 30... <shrug>
Chilie Monster;
In the US we don't do the cross coupling. Has to do with the price of putting togehter the communication lines that are remoted. In the enroute environment, the boxes are designed for it, but the wire pairings for the radio sites aren't...
regards