Hi Cintai, if you are on CSL, why do u want to go for ss, it limits your options when it comes to picking a job. the time it takes for processing of both is more or less the same, there might be just a month's difference. but if u feel strongly about a state and u dont want to go anywhere else, u can go for ss.

as for documents, u need more or less everything tht u will be sending to DIAC for your application, including ur work documents, IELTS score, assessment proof, along with a commitment statement and your asset proofs. when i say commitment statement, they want to see how much u know about the state and that u r going for the state because u want to, not becasue it is a faster route to the visa. so u write about the state, work oportunities for u, cost of living, how the place is good for u, culture, population, different areas so on n forth.
for asset proofs, they dont bother much with those from Non HR countries but when it comes to indo-asian region, they are very particular, they do check proofs, they want to see how much cash u have in ur bank for last 3 months. we gave our proofs back in april but they asked for it again to check if we were still holding it in our account and the day we sent them proofs, in two days we got our sponsorship letter.

and remember state sponsorship is taking forever these days, 3-4 months for ACT/Victoria. in our case they took 6 months (april-September)

so u can apply for the visa and then if u still feel u want to try state sponsorship, aply for it and then convert form 175 to 176