It really depends on your background and familiarity with the material covered in the courseware of each class. Reviewing the course outline for each will give you an idea of what to expect and areas to study. The classes, while available in any order, appear to build upon the last from looking at the course outlines. If you are starting with little or no in-depth knowledge of the objectives covered within each course, my recommendation is to take them sequentially (333, 423, 429). Set your self up for success.
RHS333 Details
RH423 Details
RHS429 Details
Good luck!
