Re: Is two Days a week enough?
You should train, to some capacity, every day IMO.
I'd leave a dojo that only held formal classes 2-3 days a week at this point in my life.
There is also something to be said about quality of practice. I mean there are some people who show up to 4-5 classes a week, don't push themselves, and you can see it in their Aikido. You get out of Aikido what you are willing to invest, like anything else.
Ideally, train everyday in some capacity, with your full attention.