So I tried the latest RSIM air (or what the ebay seller told me…) for my SPRINT iphone 4s. The newest version… there is no way to check what version you have under Settings, then Phone, and Sim Applications…. because… there is no sim applications.
I got a reply from Alfredo Rios about my older RSIM AIR. Thanks a ton for this tip.
Long story short… I tried IMSI 2040438 (supposedly verizon.. but also listed as China Telecom China IMSI)