If you're moving to a organic cake fertilizer, I wouldn't bother with it at this time of year. They take a while to have an impact, so you won't get much bang for your buck this year. I'd save your time/money for the spring.
If you want to move to organics in general, there are liquid organics out there that will work well. I use organics now, but I've used a lot of Miracle Grow in the past and it worked well too.
I tend to use both a slow release fertilizer and a weekly liquid. I made fertilizer cakes once or twice, but it was a pain and stinky. Now I just put together the dry mix and put it all in a tea bag and use a toothpick to hold it down. I try to get a pretty balanced mix, but tend to go a little lighter on phosphorus than nitrogen and potassium. Then I use full strength liquid fish emulsion through the growing season. I stop fertilizing when the daytime temperatures stay at or below 50.