Your post brings up a very important point missing in many of the current "young" generations thinking and posting: the concept about how good that we are.
In American schools you learn something, generally close to when you get tested on it. In many cases, you do not need KNOWLEDGE to pass the test - rather only a usable short term memory. The test score is therefore not a confirmation of knowledge, rather often a measure of how much luck with short time learning and multiple choice was possible.
Arbans is labeled Conservatory Method and I firmly believe that this is what it is - designed to be presented and monitored by professors. Those teachers with higher education are in a position to offer the student a superior "BALANCE" of basics, technical and musical exercizes and then determine when the student is capable of adding the characteristic studies.
This means that there is a PLAN based on the PERFORMANCE of the student. A student with superior tonguing could perhaps start on a different exercise than someone with superior slurring talent. One thing that a professor does not do is give a student with NONE or few of the capabilities something that will only demoralize them.
Judging from many of the posts - including the first one of this thread, NO BRAIN POWER has been spent on the players own real capabilities, if there is a realistic chance of getting this decent in a couple of weeks or not. None of the characteristic studies were designed to be worked on for two years. They were designed to give the student a sense of power and accomplishment AFTER achieving the skills necessary to master them.
To judge if you are ready, just grab the two hardest bars in your opinion. If you cannot play them "perfectly" after 15 minutes, your box of skills is missing something and you probably should be working on something "much" easier.
Thus rowuks simple rule of thumb: "if you have to ask the question, you are not ready."