Two days a week is the minimum I think one needs in order to progress. We have several in my dojo who come twice a week and they are making very nice progress. Once you can start getting into the second class with your dojo that should help some of your frustrations.
But I understand how you feel because for me twice a week would not be enough either. I train 3 days/5.5 hours a week and as far as I know my progress is just fine. This is all my dojo has to offer right now. Ive considered adding a 4th day by visiting another dojo occasionally but I really don't feel like I need it.
On the off days if I need some aikido I can do some weapons kata or some footwork or ukemi practice on my own at home and frequently do so.
As much as I would love to be able to work out 7 days a week I have to accept the fact that this body is not going to put up with that kind of abuse at my age and besides... there is life outside of the dojo. It's not like I'm in training to go to war or something after all. I have a whole lifetime to learn it.
