Hi Naif Ashraf, 

There is no Recommended Requirements Guide from Pega Robotics, However "Minimum Requirements" guide can be considered as "Recommended Requirements". Ideally "Minimum Requirements" topic from Pega Installation Guide which you have already referred would be sufficient to run even 30 or more processes.(please note you can't run two solutions at a time, you can always run one project after the other and a single solution can call 30 processes as you mentioned above)

However please follow Some of the best practices while developing the solutions:

1. Use Asynchronous links at jump start of each automation and loops, where ever needed to avoid Memory issues and crash of Robotics. 

2. Create and use controls that are really required in the flow of automation, to improve loading time and re-rematching time.

Note: In the "Minimum Requirements" guide you can refer the processor as "Dual core or faster processor" and also you can see it was mentioned as higher versions can be used where ever possible. You can use any of the higher versions as mentioned in the guide.