First Time whit a Progskeet 1.2

Hi,today i bought a progskeet 1.2 full version for downgrading my ps3 (is a fat 40gb nor Cechl-04).I had read a lot of guides for downgrading,but i have a lot of questions:

-Is necessary a USB PSjailbreak?
-It's real the the progskeet 1.2 make a lot of problems?
-What do I need besides progskeet and soldering station?

Sorry for my bad english,but i'am a italian boy ;)

Thank You