So, you're an optimist?
I suggest just use PwnageTool for now.
I think it has the activate option when you make the custom ipsw.
As for the unlock, you will need to wait for ultrasn0w to be updated.
as for SIM cutting, i suggest buying one so you don't screw up.
also, turn cellular data off, because sometimes, iphone uses data, and you get charged for minutes. I also have t-mobile prepaid.