See this thread I started. , it will give you some stats. And
HERE I explore some of the easier times to get in. As for what to buy to get it, it depends. IF one can travel off season and generally do with a 1 BR or less, many things will work out. I like cheap but good trading options and other points systems. One might consider Bluegreen or WorldMark along with several others. I have used a MX resort that works on points but isn't in a system. But one must take into account the risk, yearly fees, exchange fee and $95 resort services fee. And also the yearly II membership fee approaching $85. This makes getting a studio very hard to justify unless what you trade costs almost nothing or is for a higher demand time frame.
I have also used my Aruba weeks to trade in. With minimal up front purchase price and a yearly fee of between $360-390, I can easily justify it for a 1 BR, the studio would depend on specifics as to which resort and time of year. IMO, one needs to consistently get a resort other than OKW for adventure time to make it reasonable for a studio.
Regardless, the bottom line is buying another timeshare simply to trade for
DVC is likely unreasonable. But if one can use it, trade for other things as well and also get DVC at times, it can be a workable course.