If you do your homework 2hours a week with guidance is not insufficient. For example in my case due to distance from the dojo I get only 2hours per week with my teacher. Outside the dojo I practise at least an hour at least 5 days a week. I'll do it 7 days a week when I can. Perhaps the better question is how you use the time you have efficiently. I take advantage of dojo time to ask questions and fix bad habits. At my dojo the teacher gives homework. He tells us what to fix and how to fix it so when I can't attend training I know what to do. For new stuff we are expected to pick up whatever we can remember and keep repeating that until ready to add other things. The pace is very slow and everything is devided into parts learned separately. Only at the end is it put together. Kata are introduced litteraly one step at a time.