Is Oracle Web Applications 11i Protocol GUI Scripting Recommended?

1. Is the Oracle Web Applications 11i protocol using GUI method a stable and reliable protocol? As I have read on various forums that users should refrain from using GUI scripting for large applications.

2. The GUI protocol is a very resource intensive protocol, 50 vusers utilise 12% of CPU. So is there anyway by changing, any settings,etc. to make this protocol scalable as we need to run a load test of 1600 concurrent users. Is this possible with GUI scripting using around4-5 machines?