We pursue wisdom as a lifelong process of self cultivation. To commit to this path is to commit to greatness.
As for how long it takes to manifest understanding, it depends on what you commit to the process. As a rule of thumb, three good practice sessions per week will enable reasonable progress. If you can only get two sessions in, you will maintain your level, but slip over time. Four sessions is best.
So much depends on how you define 'Proficiency'. Our training seeks to help you change your condition. Our methods are tools for refining the body, deepening your awareness and increasing concentration.
When refining, loosening or softening the body, progress can be easily measured in terms of range of movement, pain relief and raised energy levels. Structural accomplishment is similarly easy to quantify... you are much stronger.
Since measuring progress in awareness and concentration is so difficult, we endeavor to note the external manifestations or symptoms of such progress. This is why partner training is so essential. In solo training you may feel or believe that you've improved, but as soon as you touch another person, you know. Real skills grow from this knowing awareness.
Without the honest feedback provided by vigorous partner training, progress in self cultivation and self development is just talk and conjecture.
That having been said, a reasonable level of structural integration can be reached in three years of dilligent practice. You will notice immediately more relaxation and increased energy. Going beyond this, it's hard to say how long it will take since students are so different and have such wildly different expectations. Besides, it's the journey, not the destination. Try to manage your expectations keeping in mind the present moment. This is one important aspect of "Empty Cup, Beginners' Mind".