As mentioned, book your 1BR at 12 months for your use year and bank the Studio options and book at 8 months or less depending on what week you want in your non use year as Studios are much more available at 8 months than 1BR. It also depends on what resort. e.g. Maui - the only real problem could be if you want the studio for the high use weeks like Presidents Day/4th July/Thanksgiving and possibly the late June through August period.