I've got to say, I'm very surprised by the amount of negativity towards carbon dosing. I've been carbon dosing almost the entire time I've been in this hobby. It is what allows me to run my tank without a ton of filtration media. Based on all the push to get rid of it though, I'm going to reduce my carbon dosing until I can turn it off. But that will take months since quitting cold turkey will kill a tank.
As for the GFO, again, this is being run to deal with the aftermath of my crash. I'll take it offline once I can see that my PO4 doesn't rise very quickly. I have no desire to run GFO as my permanent method. As @markalot keeps stressing, the reef roids may raise my PO4 and give me false readings, I'll reduce the reef roids to twice a week. Probably feed them the day after I do my testing.
You're the best judge knowing what you know about your tank, all we can do is offer what worked for us. I am not sure reef roids raises PO4, rather it seems to interfere with the test (hanna ULR). I would test high PO4 12 hours after feeding, test again that evening and get much lower values.