*Disclaimer - I am not a doctor.
While potassium can collect easier on Spiro, and that can mess with your body and brain's natural hormone (non sexual) system as I understand it, really you have little to fear, at least in the short term.
Story time: I had much the same reaction as you when I started HRT. One week, I went to my doctor for my shot and the doc asked how I was doing. I explained my fears about potassium and how I had adjusted my diet.
He chuckled and said, "Tori, I am not even going to test your potassium levels until the twelve month mark, mostly just electrolytes and hormones. This problem takes a good amount of time to develop. Besides, how would I get an accurate blood readings if you dramatically mess with your diet? Eat normally. Don't go out of your way to eat extra potassium. You should be fine. If there is a problem we will have plenty of time to address it before it gets out of hand. A healthy person should be able to handle a normal amount of potassium even if they are on Spiro."
So, I suspect you can just eat normally, and ASK the next time you see your doctor. They may have different opinions than my doctor... but this is not a problem that develops overnight.
Let me know if you learn anything different. I do not want to be giving out faulty info, and on this subject I am still learning.