Smartieplum, it's hard to know what will work best. You may have to try some different days and times to find the right fit for you.
My mother was so agitated by me, and it was so unpleasant for me to hear all the accusations, that I did not visit her for almost two months after she moved into her care home. My husband went once a week on weekends, during the day, usually around lunchtime. As yet seemed to work well, when I started visiting, we kept that pattern. Her best time is from about 10 am to 1 or 2 pm. She isn't good first thing in the morning and some days, the sundowning could start as early as 2 or 3. Evening visits are usually met with sundowning and increased confusion, but if we need to drop something off or talk to staff or just check on her, we do it anyway, we just don't stay.
We visit about every two weeks, which has been our "average," for the three years she has been in care. Sometimes I go on my own during the week, sometimes OH will go on his own over the weekend, usually we both go together on the weekend.
I think it all depends, and you just have to do what works. I hope you are able to figure something out. Best wishes.