is it possible to change the Protocol Profile (Client) via iRule for a specific source network?
Yes it can be done. This probably answers your question.
No, unfortunately not. I need to change the "Protocol Profile (Client)" not the SSL Profile
You can create multiple VIPs with specific profiles and then redirect request to a specific VIP based on src network
You can use enable option for profiles. I am not sure if it works
Search for keyword ::enable