Re: My thoughts about my dojo/sensei
You cannot (yet) imagine the importance of an instructor's personality in a student's training. If you click with this one, stay with him, he does know more than you anyway.
As for training only three times a week, remember, a martial class is like a piano class. You need to practice at home what you have learned in class. Wich means that you are free to practice seven days a week if you want.
You can also bring a notebook and take time to write down what you have learned right after the class. This will help you remember.
The only problem might with ukemi. You need to find at least a good thick carpet, and plenty of space. If this is difficult, try staying a few minutes after the class to roll around. Meditating can also help you. Visualize yourself executing a perfect ukemi, it will help, believe me.
Now, go train.