Why do you support this system?
A hierarchical meritocracy inherently allows for the most capable to rise, if left alone. Adopting an attitude of "up-or-out", as seen in the military (whereby those individuals who are repeatedly passed by for a promotion due to a lack of ability are eventually discharged), and an inverse rewards ratio (whereby those individuals at the top of the pyramid live in the most spartan manner and without possessions) will encourage those who are both self-sacrificing and capable to rise to the top - the two most important qualities of a benevolent autocrat.
Obviously, however, a pyramid needs a top. To this end, I would actually take a page out of the democratic handbook. Democracy in not inherently bad, after all - it is a problem of who votes, not the act itself. I would, among the top leaders of the hierarchy, allow for citizens to vote for a leader. This comes with caveats on the concept of citizenship. I would class people into two basic political classes: citizens and nationals. All those born of a nation are, by virtue of their blood, culture and language, a part of that nation. Once 16, they may opt to become citizens - after performing at least a year of service for their country. This can be civil, social, or even militant. They may volunteer to be a doctor, a teacher, or even a simple laborer whose services help maintain national infrastructure. Naturally, the proper qualifications would need to be met. At the conclusion of their service, these nationals would become citizens. As citizens, they may participate in the political hierarchy, and this would include voting among a list of candidates (the top three or so in the hierarchy) for an autocrat. This autocrat would be able to be impeached by referendum at any time among citizens - to prevent cronyism in the top echelons of the hierarchy. However, given the fact that the autocrat would live frugally, ingloriously, and perpetually in service, it is unlikely that those that are power-hungry or greedy for wealth would seek the position in the first place.
I appear to have answered all your questions, actually.
It bears adding that this is a simply a rough conception of what my ideal system would look like. It is impractical to implement in the real world, and likely has holes that do not appear in initial thought. It is also incomplete, as I do believe in a degree of economic syndicalism, which would form a parallel system to the political hierarchy, under a single top council and the autocrat.